Consolidated Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,415,381,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                642,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts receivable - trade | 
                                                2,036,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,415,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Merchandise and finished goods | 
                                                124,677,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                181,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                163,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                155,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                1,024,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,199,525,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                100,489,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                68,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -4,499,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -6,320,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                7,036,344,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,665,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                4,482,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,568,732,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                972,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                972,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets, net | 
                                                2,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                634,422,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                727,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Buildings and structures | 
                                                7,599,593,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,569,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -5,686,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,612,543,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings and structures, net | 
                                                1,912,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,957,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Leased assets | 
                                                17,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -15,410,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -13,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Vehicles | 
                                                32,903,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -29,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -29,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Vehicles, net | 
                                                3,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Leased assets | 
                                                486,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                902,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                2,043,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other intangible assets | ||
| Intangible assets | 
                                                170,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                214,455,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Software | 
                                                167,646,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                211,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                2,783,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,756,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investment securities | 
                                                2,752,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,717,886,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                31,671,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,584,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Retirement benefit asset | 
                                                53,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                7,436,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,539,659,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                14,473,245,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,204,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Non-current liabilities | 
                                                3,306,891,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,083,044,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Long-term borrowings | 
                                                2,166,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,950,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                286,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                267,024,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                18,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax liabilities | 
                                                792,347,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                803,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                5,204,422,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,967,778,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Short-term borrowings | 
                                                400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                3,343,915,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,158,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                8,511,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,050,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                3,419,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,612,730,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                738,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                738,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                245,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                245,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                2,514,631,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,676,752,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -79,272,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -47,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                1,609,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,585,992,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                1,609,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,585,992,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                20,393,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                30,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-controlling interests | 
                                                912,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                925,049,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                5,961,931,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,153,927,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                14,473,245,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,204,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Current portion of long-term borrowings | 
                                                940,769,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                874,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                2,773,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,754,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                11,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                60,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                41,729,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                110,874,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                257,558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                310,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Other | 
                                                43,564,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                43,564,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |