Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Subtotal | 
                                                316,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                149,747,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                64,727,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | 
                                                -247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -688,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,304,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | 
                                                -572,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                315,986,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                148,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                62,596,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | 
                                                -3,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,972,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -10,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | 
                                                -220,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,880,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -3,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -7,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -10,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||||
| Repayments of long-term borrowings | 
                                                -5,618,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -20,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -27,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -5,618,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -20,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -27,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                306,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                119,677,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,532,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                771,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                465,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                345,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                320,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |