Consolidated Balance Sheet
| Concept | As at 2023-09-30 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                295,221,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                386,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                247,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                273,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                104,184,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                130,482,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                697,304,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                843,520,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                1,490,787,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,523,346,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                875,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                953,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                8,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                544,825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                511,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                159,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                159,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings, net | 
                                                338,920,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                313,677,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other, net | 
                                                46,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,785,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Own-used assets | ||
| Other | — | — | 
| Intangible assets | 
                                                70,149,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                58,094,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Investments and other assets | ||
| Assets | 
                                                2,188,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Long-term borrowings | 
                                                226,298,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                252,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                17,322,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                684,941,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                732,145,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                180,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                194,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Short-term borrowings | 
                                                106,665,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                122,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                99,772,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                92,849,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                15,975,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                49,153,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                43,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accrued expenses | 
                                                293,308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                281,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                32,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,293,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                307,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                272,370,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                18,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                56,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                994,297,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,023,983,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,679,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,756,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                508,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                610,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                50,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                50,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                3,132,425,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,132,425,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                -2,514,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,412,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -159,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -159,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                508,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                610,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                2,188,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity |