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 | 
                                                737,806,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                744,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                67,121,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                96,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -1,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                1,281,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,399,967,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Property, plant and equipment | 
                                                425,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                426,694,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Tools, furniture and fixtures | — | — | 
| Tools, furniture and fixtures, net | 
                                                58,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                50,434,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                91,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                91,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets | — | — | 
| Leased assets, net | 
                                                20,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investment securities | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                243,299,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                248,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                55,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                63,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                14,294,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                669,228,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                674,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                1,950,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,074,747,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Accounts payable - trade | 
                                                222,178,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                209,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Short-term borrowings | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                11,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,802,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                27,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,119,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                58,589,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                103,917,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                809,364,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                905,716,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts payable - other | 
                                                218,686,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                229,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Non-current liabilities | 
                                                596,344,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                657,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Long-term borrowings | 
                                                497,723,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                554,378,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                11,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,709,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                86,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                85,862,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,405,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,563,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other liabilities | — | — | 
| Provision for bonuses | 
                                                8,945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other liabilities | — | — | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | ||
| Retained earnings | 
                                                531,998,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                498,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                544,998,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                511,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                544,998,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                511,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                1,950,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,074,747,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |