Key Financial Data Of Group
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | — | 
                                                4,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,286,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,089,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                248,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | 
                                                211,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                247,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                69,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | 
                                                239,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                703,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                282,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                10,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,732,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,501,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                16,086,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,356,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,867,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                107.07
                                                
                                             | 
                                                121.11
                                                
                                             | — | — | 
                                                33.32
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.679
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.699
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.706
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                654,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -873,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -310,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -895,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -614,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                39,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -80,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                3,096,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,712,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,844,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |