Quarterly Statement Of Cash Flows
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|---|
| Quarterly statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Subtotal | 
                                                319,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                860,958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                959,148,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | 
                                                1,529,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                771,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | 
                                                -831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | 
                                                -95,140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -159,387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -336,725,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                224,952,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                704,684,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                622,208,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | 
                                                -60,691,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -124,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -195,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,721,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | 
                                                131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                77,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                772,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -60,612,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -183,611,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -457,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||||
| Repayments of long-term borrowings | 
                                                -9,550,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -107,920,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -644,426,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -126,462,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -230,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -463,617,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                37,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                290,079,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -298,647,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                2,198,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,160,356,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,870,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,168,924,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |