Semi-Annual Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-03-31 | 
|---|---|---|
| Semi-annual balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,646,248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,676,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                112,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                3,877,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,123,528,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Property, plant and equipment | 
                                                3,805,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,618,537,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                764,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                764,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets | — | — | 
| Leased assets, net | 
                                                84,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                98,329,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                811,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                620,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | — | — | 
| Other, net | 
                                                38,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                37,451,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Intangible assets | 
                                                16,177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,411,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investment securities | 
                                                33,837,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                34,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                220,513,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                221,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                40,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                146,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                147,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                4,042,544,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,864,356,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                7,919,991,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,987,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                1,178,621,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,039,240,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                22,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                3,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                31,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                123,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                87,498,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                2,752,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,509,950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts payable - other | 
                                                177,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                218,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Non-current liabilities | 
                                                3,556,402,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,784,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Long-term borrowings | 
                                                3,186,322,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,407,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                51,913,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                62,977,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                80,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                6,308,855,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,294,299,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other liabilities | — | — | 
| Provision for bonuses | 
                                                74,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,051,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax liabilities | 
                                                40,309,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                40,375,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other liabilities | — | — | 
| Net assets | ||
| Share capital | 
                                                1,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,495,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | ||
| Capital surplus | ||
| Capital surplus | 
                                                359,320,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                734,225,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | ||
| Retained earnings | 
                                                118,803,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,669,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -429,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -429,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                1,477,694,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,559,625,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | ||
| Valuation difference on available-for-sale securities | 
                                                970,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred gains or losses on hedges | 
                                                28,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                133,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                133,907,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,611,136,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,693,584,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                7,919,991,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,987,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |