Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | 
                                                149,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                253,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -202,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                1,377,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,459,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Impairment losses | — | — | 
                                                90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                35,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -40,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                198,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Foreign exchange losses (gains) | — | — | 
                                                -17,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -349,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                168,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                74,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -1,104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,011,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -311,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                206,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                -33,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                260,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                59,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                51,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                -265,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                296,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -1,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of investment securities | — | — | 
                                                204,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -5,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -1,655,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Proceeds from long-term borrowings | — | — | 
                                                3,350,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,350,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -2,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,805,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -182,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -182,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -135,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -305,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,447,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | — | 
                                                47,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                66,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                -2,178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,329,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | 
                                                7,021,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,529,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |