Consolidated Statement Of Cash Flows
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | — | 
                                                -173,941,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                121,679,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -15,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -8,633,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -2,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -16,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -190,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                101,943,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | — | 
                                                -208,650,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -205,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                23,178,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -283,865,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -241,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | 
                                                -30,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -30,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                -14,660,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -8,675,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Proceeds from issuance of shares | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from long-term borrowings | — | 
                                                1,100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                740,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of long-term borrowings | — | 
                                                -580,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -406,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                506,652,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                330,174,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                31,987,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                190,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                1,503,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,471,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,272,925,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,082,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |