Statement Of Cash Flows
| Concept | 
                                    
                                        2023-04-01 to 2024-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                                
                                    
                                        2023-04-01 to 2024-03-31  | 
                            
                                
                                    
                                        As at 2023-03-31  | 
                            
                                
                                    
                                        2022-04-01 to 2023-03-31  | 
                            
                                
                                    
                                        2022-04-01 to 2023-03-31  | 
                            
                                
                                    
                                        As at 2022-03-31  | 
                            
                        
|---|---|---|---|---|---|---|---|
| Statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | 
                                        
                                             
                                                -1,697,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -1,508,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -791,976,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                -657,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Depreciation | 
                                        
                                             
                                                27,945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                37,321,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Increase (decrease) in allowance for doubtful accounts | 
                                        
                                             
                                                -88,681,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -82,220,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest and dividend income | 
                                        
                                             
                                                -48,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -43,159,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest expenses | 
                                        
                                             
                                                31,837,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                18,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Decrease (increase) in inventories | 
                                        
                                             
                                                80,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -137,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Increase (decrease) in trade payables | 
                                        
                                             
                                                -152,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Subtotal | 
                                        
                                             
                                                -944,404,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -699,411,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest and dividends received | 
                                        
                                             
                                                434,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                79,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest paid | 
                                        
                                             
                                                -31,858,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -18,767,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Income taxes paid | 
                                        
                                             
                                                -27,290,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -92,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from operating activities | |||||||
| Other, net | 
                                        
                                             
                                                16,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                32,251,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from operating activities | |||||||
| Impairment losses | 
                                        
                                             
                                                754,813,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                56,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Foreign exchange losses (gains) | 
                                        
                                             
                                                -368,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -227,758,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Loss (gain) on sale of property, plant and equipment | 
                                        
                                             
                                                2,850,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -156,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Decrease (increase) in trade receivables | 
                                        
                                             
                                                31,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                392,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Net cash provided by (used in) operating activities | 
                                        
                                             
                                                -954,486,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -1,021,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Decrease (increase) in other assets | 
                                        
                                             
                                                3,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                76,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Increase (decrease) in other liabilities | 
                                        
                                             
                                                -129,387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -174,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | 
                                        
                                             
                                                -16,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -17,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Proceeds from sale of property, plant and equipment | 
                                        
                                             
                                                18,685,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                63,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Net cash provided by (used in) investing activities | 
                                        
                                             
                                                -6,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                941,509,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Loan advances | 
                                        
                                             
                                                -18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -52,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Other, net | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -4,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Proceeds from collection of loans receivable | 
                                        
                                             
                                                5,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from facilities maintenance and investing activities | |||||||
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | 
                                        
                                             
                                                -82,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -75,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Dividends paid | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Proceeds from issuance of bonds | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                38,956,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Proceeds from long-term borrowings | 
                                        
                                             
                                                600,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                20,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Redemption of bonds | 
                                        
                                             
                                                -87,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -77,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Repayments of long-term borrowings | 
                                        
                                             
                                                -194,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -132,779,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Net cash provided by (used in) financing activities | 
                                        
                                             
                                                629,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -576,730,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Other, net | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -4,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                        
                                             
                                                1,943,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                3,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Net increase (decrease) in cash and cash equivalents | 
                                        
                                             
                                                -329,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
                                        
                                             
                                                -653,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash and cash equivalents | — | 
                                        
                                             
                                                974,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                1,303,797,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,956,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     |