Quarterly 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 | 
|---|---|---|---|---|---|---|
| Quarterly statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | — | 
                                                1,170,325,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                532,178,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                2,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,752,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -1,475,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -147,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -39,359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,023,390,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                521,856,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of securities | — | 
                                                -500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -300,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of property, plant and equipment | — | 
                                                -44,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -10,709,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | 
                                                -200,243,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -241,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -1,067,954,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -456,786,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Repayments of long-term borrowings | — | 
                                                -212,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -32,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | — | 
                                                -82,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -55,093,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -402,093,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -95,827,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                14,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -446,647,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -30,743,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                3,926,038,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,372,686,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,854,952,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,885,695,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |