Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | 
                                                3,094,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,785,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,815,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                1,002,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                968,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -141,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Share of loss (profit) of entities accounted for using equity method | — | — | 
                                                22,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Loss (gain) on sale of property, plant and equipment | — | — | 
                                                -6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                111,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -85,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                -44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -106,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -529,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                222,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                3,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,856,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                141,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -42,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -982,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -938,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                2,842,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,982,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -136,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -2,238,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -34,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -2,447,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -553,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                -909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -1,053,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -2,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,749,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                -2,422,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                679,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | 
                                                4,529,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,952,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,272,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |