Semi-Annual Consolidated Balance Sheet
| Concept | As at 2024-06-30 | As at 2023-12-31 | 
|---|---|---|
| Semi-annual consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,010,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,416,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                125,475,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                136,403,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -364,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -415,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                2,161,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,710,101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                13,021,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,547,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Intangible assets | ||
| Intangible assets | 
                                                3,222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,145,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                515,650,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                287,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investment securities | 
                                                299,682,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                46,259,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                58,083,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                176,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                158,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -7,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -7,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                531,893,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                303,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                2,693,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,013,606,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Income taxes payable | 
                                                6,622,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                46,987,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                303,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                340,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                1,101,934,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,417,267,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Lease liabilities | 
                                                57,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                403,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                12,818,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,764,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                177,297,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                144,550,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,279,232,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,561,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for retirement benefits for directors (and other officers) | 
                                                80,031,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,041,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses | 
                                                25,807,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses for directors (and other officers) | 
                                                2,496,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                328,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                319,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                128,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                119,356,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                1,022,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,084,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -73,591,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -73,556,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                1,405,652,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,450,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | ||
| Valuation difference on available-for-sale securities | 
                                                8,521,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                8,521,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,414,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,451,788,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                2,693,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,013,606,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |