Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-09-30 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Profit (loss) before income taxes | 
                                                754,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                373,676,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Depreciation | 
                                                256,375,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                153,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividend income | 
                                                -816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -273,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest expenses | 
                                                11,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,333,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Decrease (increase) in trade receivables | 
                                                318,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -356,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Decrease (increase) in inventories | 
                                                1,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in trade payables | 
                                                -92,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                110,237,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -83,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                125,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Subtotal | 
                                                645,577,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                408,922,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                273,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -11,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,215,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                561,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                160,290,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -3,115,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -366,183,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                496,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,922,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of shares of subsidiaries resulting in change in scope of consolidation | 
                                                -1,001,023,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -71,767,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -53,503,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                841,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -3,634,222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -416,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | 
                                                4,950,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                420,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -761,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -372,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Redemption of bonds | 
                                                -28,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -33,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of shares | 
                                                8,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                430,475,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | 
                                                -198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -75,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -70,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid to non-controlling interests | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -20,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                4,511,572,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                757,609,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                -294,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                1,438,359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                501,231,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                2,240,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                802,343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,355,784,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,854,553,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |