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 | 
                                                965,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,601,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                804,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                99,816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                79,043,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,872,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                842,328,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                835,543,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                798,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                1,285,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,375,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,335,261,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                56.90
                                                
                                             | — | — | 
                                                49.02
                                                
                                             | 
                                                18.51
                                                
                                             | — | 
| Diluted earnings per share | 
                                                56.03
                                                
                                             | — | — | 
                                                48.30
                                                
                                             | 
                                                18.24
                                                
                                             | — | 
| Equity-to-asset ratio | — | 
                                                0.541
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.500
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.490
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                101,544,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                136,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                139,916,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -60,973,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -132,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -134,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -74,344,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -123,243,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -66,700,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                368,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                402,015,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                460,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |