Consolidated Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Consolidated balance sheet | ||||||||||||||||||||||||||||||
| Balance sheet | ||||||||||||||||||||||||||||||
| Assets | ||||||||||||||||||||||||||||||
| Non-current assets | — | — | — | — | — | — | 
                                                1,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | — | — | — | — | — | — | 
                                                1,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Guarantee deposits | — | — | — | — | — | — | 
                                                1,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | ||||||||||||||||||||||||||||||
| Cash and deposits | — | — | — | — | — | — | 
                                                2,313,475,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,136,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accounts receivable - trade | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                7,560,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Prepaid expenses | — | — | — | — | — | — | 
                                                23,966,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Raw materials and supplies | — | — | — | — | — | — | 
                                                294,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                364,056,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | 
                                                27,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Advance payments to suppliers | — | — | — | — | — | — | 
                                                66,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                21,065,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | — | — | — | — | — | — | 
                                                2,755,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,617,617,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | ||||||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Property, plant and equipment | ||||||||||||||||||||||||||||||
| Investments and other assets | ||||||||||||||||||||||||||||||
| Assets | — | — | — | — | — | — | 
                                                2,757,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,618,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | ||||||||||||||||||||||||||||||
| Non-current liabilities | ||||||||||||||||||||||||||||||
| Non-current liabilities | — | — | — | — | — | — | 
                                                520,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                387,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Asset retirement obligations | — | — | — | — | — | — | 
                                                2,305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | ||||||||||||||||||||||||||||||
| Deposits received | — | — | — | — | — | — | 
                                                3,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,694,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accounts payable - other | — | — | — | — | — | — | 
                                                36,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                171,662,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Income taxes payable | — | — | — | — | — | — | 
                                                1,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accrued expenses | — | — | — | — | — | — | 
                                                21,494,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,206,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | — | — | — | — | — | — | 
                                                128,172,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                209,054,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Advances received | — | — | — | — | — | — | 
                                                64,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                26,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | — | — | — | — | — | — | 
                                                648,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                596,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities and net assets | ||||||||||||||||||||||||||||||
| Shareholders' equity | — | — | — | — | — | — | 
                                                2,089,944,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,007,006,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Share capital | — | — | — | — | — | — | 
                                                11,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                97,546,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Capital surplus | — | — | — | — | — | — | 
                                                2,835,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,095,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retained earnings | — | — | — | — | — | — | 
                                                -756,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,185,981,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Treasury shares | — | — | — | — | — | — | 
                                                -106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -75,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Share acquisition rights | — | — | — | — | — | — | 
                                                18,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | 
                                                18,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                564,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -756,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,089,944,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,271,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,108,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,835,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -756,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,021,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,531,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,095,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,007,006,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                97,546,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,185,981,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,185,981,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                564,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -75,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -331,829,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                59,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,789,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,057,848,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,785,820,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -75,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -331,829,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                564,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,493,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | — | — | — | — | — | — | 
                                                2,757,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,618,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | ||||||||||||||||||||||||||||||
| Shareholders' equity |