Consolidated Statement Of Cash Flows
| Concept | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | — | 
                                                922,909,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                186,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                4,550,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -41,111,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -27,639,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                705,840,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -17,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | — | 
                                                -105,962,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -91,782,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -64,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -108,723,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | — | 
                                                -2,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -12,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | — | 
                                                -130,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | — | 
                                                -24,073,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from long-term borrowings | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | — | 
                                                -146,230,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -325,048,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -333,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                492,891,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                -28,031,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -28,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                307,773,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                366,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                1,169,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                861,694,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                495,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |