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 | ||||||
| Profit (loss) before tax | — | 
                                                12,898,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                49,439,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                24,318,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss), attributable to owners of parent | — | 
                                                8,105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,571,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income, attributable to owners of parent | — | 
                                                794,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,024,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                29,798,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Equity attributable to owners of parent | 
                                                493,965,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                399,923,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                376,258,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                1,363,593,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,410,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,021,647,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                31.09
                                                
                                             | 
                                                130.51
                                                
                                             | — | — | 
                                                64.92
                                                
                                             | 
| Diluted earnings (loss) per share | — | 
                                                28.43
                                                
                                             | 
                                                130.17
                                                
                                             | — | — | 
                                                64.75
                                                
                                             | 
| Ratio of owners' equity to gross assets | 
                                                0.362
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.284
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.368
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Cash flows from (used in) operating activities | — | 
                                                40,207,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,916,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -680,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash flows from (used in) investing activities | — | 
                                                -29,980,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -279,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -42,396,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash flows from (used in) financing activities | — | 
                                                -6,672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                261,316,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                43,768,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                117,030,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                113,421,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                92,959,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |