Key Financial Data Of Reporting Company
| 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 reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | — | 
                                                5,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,168,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,836,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                -294,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                615,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                524,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                17,520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,319,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,152,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                19,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,394,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,692,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                -19.55
                                                
                                             | 
                                                37.01
                                                
                                             | — | — | 
                                                30.05
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.879
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.856
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.877
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -748,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                903,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -935,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -612,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -502,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -160,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -153,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                10,501,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,687,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,361,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |