Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                262,114,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                386,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                321,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                273,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                145,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                130,482,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -1,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                778,520,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                843,520,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                1,444,147,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,523,346,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                850,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                953,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                7,834,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                522,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                511,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                159,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                159,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings, net | 
                                                320,317,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                313,677,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other, net | 
                                                42,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,785,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Own-used assets | ||
| Other | — | — | 
| Intangible assets | 
                                                71,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                58,094,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Investments and other assets | ||
| Assets | 
                                                2,222,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Long-term borrowings | 
                                                218,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                252,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                16,094,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                673,212,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                732,145,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                177,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                194,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Short-term borrowings | 
                                                108,664,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                122,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                111,579,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                92,849,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                24,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                45,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                43,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accrued expenses | 
                                                316,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                281,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                11,309,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,293,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                305,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                272,370,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                25,643,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                56,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                1,017,690,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,023,983,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,690,902,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,756,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                531,765,000
                                                
                                                    
                                                        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 | 
                                                -2,491,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,412,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -159,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -159,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                531,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                610,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                2,222,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity |