Consolidated Statement Of Cash Flows
| Concept | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2022-09-30 | As at 2022-09-30 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                42,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                412,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -10,848,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -67,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                53,201,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                358,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,329,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -3,288,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -26,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -348,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -295,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Dividends paid | 
                                                -96,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -76,906,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -96,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -74,922,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                1,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -44,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                258,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                2,665,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,710,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,784,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,525,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |