Semi-Annual Consolidated Balance Sheet
| Concept | As at 2024-03-31 | As at 2023-12-31 | 
|---|---|---|
| Semi-annual consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                1,619,499,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,275,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                9,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,977,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -152,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                2,962,519,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,323,137,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                1,637,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,653,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Land | 
                                                216,779,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                216,779,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Other | 
                                                945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                29,976,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                35,404,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                62,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                57,573,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Non-current assets | 
                                                1,730,177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,746,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                4,692,697,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,069,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Notes and accounts payable - trade | 
                                                506,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                276,031,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                12,149,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                101,625,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                325,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                300,749,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                1,291,594,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,017,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                383,324,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                383,324,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                1,674,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,017,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses | 
                                                57,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Share capital | 
                                                358,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                358,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                362,276,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                362,276,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                2,297,705,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,332,038,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Shareholders' equity | 
                                                3,017,778,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,052,111,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                3,017,778,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,052,111,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                4,692,697,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,069,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |