Consolidated Statement Of Cash Flows
| Concept | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | As at 2022-09-30 | 2022-04-01 to 2022-09-30 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | — | 
                                                369,892,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                351,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                21,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                27,527,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -67,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -72,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -111,972,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -80,357,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                279,633,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                298,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | — | 
                                                -115,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -120,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | 
                                                -700,299,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -999,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                110,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -205,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                89,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Dividends paid | — | 
                                                -47,350,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -47,585,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid to non-controlling interests | — | 
                                                -3,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -54,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -54,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                336,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                39,258,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                3,777,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,441,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,371,870,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,332,612,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |