Quarterly Balance Sheet
| Concept | As at 2025-03-31 | As at 2024-09-30 | 
|---|---|---|
| Quarterly balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,886,137,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,313,475,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                250,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                294,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                14,184,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                2,265,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,755,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Investments and other assets | 
                                                24,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Non-current assets | 
                                                24,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                2,290,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,757,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Income taxes payable | 
                                                745,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                3,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                13,574,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                155,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                128,172,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Asset retirement obligations | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                525,571,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                520,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                681,397,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                648,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                12,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                2,841,101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,835,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                -1,268,943,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -756,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                1,584,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,089,944,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                24,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,608,710,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,108,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                2,290,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,757,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |