Consolidated Balance Sheet
| Concept | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Consolidated balance sheet | ||||||||||||||||||||||||
| Balance sheet | ||||||||||||||||||||||||
| Assets | ||||||||||||||||||||||||
| Current assets | ||||||||||||||||||||||||
| Cash and deposits | — | — | — | 
                                                3,052,570,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,873,773,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accounts receivable - trade | — | — | — | 
                                                20,938,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                17,118,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accounts receivable - other | — | — | — | 
                                                73,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                6,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Merchandise and finished goods | — | — | — | 
                                                37,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                34,856,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Prepaid expenses | — | — | — | 
                                                51,492,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                16,460,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Advance payments to suppliers | — | — | — | 
                                                16,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                897,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | 
                                                7,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                431,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | — | — | — | 
                                                3,240,117,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,987,440,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | — | — | — | 
                                                277,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                227,368,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | — | — | — | 
                                                131,873,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                53,024,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments in capital | — | — | — | 
                                                10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Long-term prepaid expenses | — | — | — | 
                                                81,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | ||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | 
                                                141,837,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                169,970,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Property, plant and equipment | ||||||||||||||||||||||||
| Intangible assets | ||||||||||||||||||||||||
| Patent right | — | — | — | 
                                                2,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                2,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | 
                                                500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other intangible assets | ||||||||||||||||||||||||
| Intangible assets | — | — | — | 
                                                4,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                4,374,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Software | — | — | — | 
                                                1,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | ||||||||||||||||||||||||
| Assets | — | — | — | 
                                                3,518,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                4,214,809,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | ||||||||||||||||||||||||
| Current liabilities | ||||||||||||||||||||||||
| Short-term borrowings | — | — | — | 
                                                507,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                550,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Deposits received | — | — | — | 
                                                9,946,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                8,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Income taxes payable | — | — | — | 
                                                16,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                16,503,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accounts payable - other | — | — | — | 
                                                42,796,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                30,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current portion of long-term borrowings | — | — | — | 
                                                18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accrued expenses | — | — | — | 
                                                16,006,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                19,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | — | — | — | 
                                                648,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                666,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Advances received | — | — | — | 
                                                1,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                2,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Unearned revenue | — | — | — | 
                                                20,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                19,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | ||||||||||||||||||||||||
| Long-term borrowings | — | — | — | 
                                                327,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                345,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | — | — | — | 
                                                327,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                345,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | — | — | — | 
                                                975,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,011,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities and net assets | ||||||||||||||||||||||||
| Shareholders' equity | — | — | — | 
                                                2,493,095,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,202,767,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Share capital | — | — | — | 
                                                1,364,728,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,283,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Capital surplus | — | — | — | 
                                                3,986,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,905,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retained earnings | — | — | — | 
                                                -2,858,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -1,986,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Share acquisition rights | — | — | — | 
                                                49,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | 
                                                49,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,858,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,986,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,542,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,364,728,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,986,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,858,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,493,095,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,283,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,203,469,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,986,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,202,767,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,905,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,905,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,986,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,396,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,769,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,893,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,893,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,769,099,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,272,005,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,396,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | — | — | — | 
                                                3,518,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                4,214,809,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | ||||||||||||||||||||||||
| Shareholders' equity |