Key Financial Data Of Reporting Company
| Concept | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | 
|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | 
                                                1,297,767,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,098,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,208,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                105,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                14,072,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                138,850,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                1,006,498,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                810,290,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                748,620,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                1,923,924,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,686,792,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,628,824,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                73.66
                                                
                                             | — | — | 
                                                59.68
                                                
                                             | 
                                                35.27
                                                
                                             | — | 
| Diluted earnings per share | 
                                                73.02
                                                
                                             | — | — | 
                                                58.16
                                                
                                             | 
                                                34.33
                                                
                                             | — | 
| Equity-to-asset ratio | — | 
                                                0.523
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.480
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.460
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                59,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -35,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -2,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                95,583,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -11,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                186,114,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                139,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                759,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                714,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                606,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |