Key Financial Data Of Group
| Concept | 2023-04-01 to 2023-12-31 | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | 
                                                170,760,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                211,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                162,811,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                13,882,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                17,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                9,646,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,529,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,810,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                10,125,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,558,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,815,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                146,485,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                140,171,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                138,428,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                305,906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                298,623,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                310,293,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                117.84
                                                
                                             | — | 
                                                55.25
                                                
                                             | — | 
                                                140.87
                                                
                                             | — | 
                                                119.87
                                                
                                             | 
                                                69.39
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.477
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.467
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.444
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                19,415,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                20,071,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,519,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -8,313,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -34,306,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -21,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -9,420,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,745,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                23,936,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                25,745,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |