Consolidated Statement Of Cash Flows
| Concept | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | As at 2022-09-30 | 2022-04-01 to 2022-09-30 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | — | 
                                                296,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                316,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                93,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -8,353,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -9,461,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                384,596,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                92,489,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of securities | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of property, plant and equipment | — | 
                                                -182,685,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -134,343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -184,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -832,044,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                -1,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Proceeds from issuance of shares | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                61,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from long-term borrowings | — | 
                                                50,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of long-term borrowings | — | 
                                                -373,690,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -412,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -336,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -359,756,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -136,591,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,099,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                1,317,925,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,454,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                911,055,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,010,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |