Key Financial Data Of Reporting Company
| Concept | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2023-09-30 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2022-11-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||
| Business results of reporting company | ||||||||||||||
| Net sales | — | — | — | — | — | — | 
                                                4,313,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,814,274,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Operating revenue | — | — | — | 
                                                831,253,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                136,961,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | — | 
                                                580,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                494,393,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                343,522,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | — | — | 
                                                562,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                5,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | — | — | — | — | — | — | — | — | 
                                                277,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                88,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total number of issued shares | — | — | — | — | — | — | — | — | 
                                                2,479,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                1,064,900
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
| Net assets | — | — | 
                                                2,642,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,109,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,937,403,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,167,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | — | 
                                                3,868,466,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,232,333,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,739,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,254,283,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets per share | — | — | 
                                                1,065.73
                                                
                                             | — | — | — | — | — | 
                                                850.71
                                                
                                             | — | 
                                                909.66
                                                
                                             | 
                                                548.05
                                                
                                             | — | — | 
| Dividend paid per share | — | — | — | 
                                                50.20
                                                
                                             | — | — | — | — | — | — | — | — | — |  | 
| Interim dividend paid per share | — | — | — |  | — | — | — | — | — | — | — | — | — |  | 
| Basic earnings (loss) per share | — | — | — | 
                                                260.09
                                                
                                             | — | — | 
                                                150.50
                                                
                                             | — | — | — | — | — | 
                                                116.35
                                                
                                             | 
                                                2.47
                                                
                                             | 
| Diluted earnings per share | — | — | — | 
                                                259.73
                                                
                                             | — | — | 
                                                150.30
                                                
                                             | — | — | — | — | — |  |  | 
| Equity-to-asset ratio | — | — | 
                                                0.683
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.945
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.931
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Rate of return on equity | — | — | — | 
                                                0.343
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.142
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.137
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.005
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | — | — | 
                                                3.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                6.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Payout ratio | — | — | — | 
                                                0.193
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | 
                                                639,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                195,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | 
                                                -36,823,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -65,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | 
                                                374,997,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | 
                                                2,226,662,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,249,064,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                73
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                69
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Average number of temporary employees | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Total shareholder return | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Total return on share price index | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |