Consolidated Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | ||
| Property, plant and equipment | ||
| Property, plant and equipment | 
                                                534,778,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                514,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Intangible assets | 
                                                16,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,079,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investments and other assets | 
                                                71,558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                41,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                623,287,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                572,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                4,603,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,561,008,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Securities | 
                                                186,769,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                2,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                3,329,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,033,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                12,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Inventories | 
                                                16,129,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,043,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                328,345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,768,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                5,137,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,612,137,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                5,760,567,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,184,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Deferred tax liabilities | 
                                                6,218,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                34,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                34,945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                28,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Deposits received | 
                                                20,399,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts payable - other | 
                                                88,687,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                91,670,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                23,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                46,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                141,681,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                166,015,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                176,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                5,570,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,974,510,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                1,625,770,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,594,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                6,524,601,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,493,705,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                -2,568,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,102,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -12,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -12,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                1,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                1,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                10,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,766,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-controlling interests | 
                                                3,059,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                5,584,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,983,777,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                5,760,567,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,184,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |