Consolidated Statement Of Cash Flows
| Concept | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Profit (loss) before income taxes | 
                                                3,016,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,207,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,619,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Depreciation | 
                                                400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Interest expenses | 
                                                6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Increase (decrease) in provision for bonuses | 
                                                147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Subtotal | 
                                                3,625,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Decrease (increase) in trade receivables | 
                                                -218,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Income taxes paid | 
                                                -320,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Net cash provided by (used in) operating activities | 
                                                3,299,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Other, net | 
                                                214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Interest and dividends received | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Interest paid | 
                                                -6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from investing activities | |||||
| Payments into time deposits | 
                                                -1,060,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -1,078,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from financing activities | |||||
| Repayments of short-term borrowings | 
                                                -2,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Dividends paid | 
                                                -1,290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -2,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Repayments of lease liabilities | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Other, net | 
                                                -22,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                20,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -530,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
| Cash and cash equivalents | — | 
                                                9,904,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,434,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |