Semi-Annual Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Semi-annual consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                9,924,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,725,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                430,629,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                501,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                12,143,711,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,469,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                10,206,499,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,214,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Buildings and structures | — | — | 
| Buildings and structures, net | 
                                                2,687,968,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,138,535,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Machinery, equipment and vehicles | — | — | 
| Machinery, equipment and vehicles, net | 
                                                503,044,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                382,679,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                6,442,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,442,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | — | — | 
| Other, net | 
                                                573,352,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                251,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Other | 
                                                96,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                96,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                2,318,245,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,378,485,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investment securities | 
                                                771,727,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                712,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Long-term loans receivable | 
                                                39,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                43,017,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                90,266,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                129,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                44,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                12,621,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,687,561,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                24,765,072,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,156,766,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Notes and accounts payable - trade | 
                                                992,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                772,579,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                195,723,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                124,524,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                542,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                445,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                4,909,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,700,464,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                2,138,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,681,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                481,919,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                477,123,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                38,335,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                41,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                2,979,933,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,519,739,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                7,889,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,220,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses | 
                                                97,478,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                246,107,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                9,090,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,090,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                6,192,923,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,192,923,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                1,476,698,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                633,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -147,911,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -184,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                16,612,363,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,732,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | ||
| Valuation difference on available-for-sale securities | 
                                                263,734,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                204,695,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                -288,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                263,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                204,179,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                16,875,809,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,936,562,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                24,765,072,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,156,766,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |