Quarterly Consolidated Balance Sheet
| Concept | As at 2024-03-31 | As at 2023-12-31 | 
|---|---|---|
| Quarterly consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,387,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,867,264,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                31,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                1,886,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,137,959,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                16,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,010,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Intangible assets | ||
| Other | 
                                                3,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                75,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                86,510,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                138,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                138,890,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Other | 
                                                150,130,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                150,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -11,924,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -11,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                230,420,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                235,411,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                2,117,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,373,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Income taxes payable | 
                                                5,158,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                16,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,412,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                154,727,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                194,008,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                373,714,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                269,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                24,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                1,003,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                899,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,158,564,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,093,606,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                831,617,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                831,617,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                2,889,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,889,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                -2,763,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,442,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                958,248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,279,101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | ||
| Valuation difference on available-for-sale securities | 
                                                -142,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -36,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                -142,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -36,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                958,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,279,764,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                2,117,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,373,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |