Semi-Annual Consolidated Balance Sheet
| Concept | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2024-02-29 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2023-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | As at 2022-02-28 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Semi-annual consolidated balance sheet | ||||||||||||||||||||||||
| Balance sheet | ||||||||||||||||||||||||
| Assets | ||||||||||||||||||||||||
| Current assets | ||||||||||||||||||||||||
| Cash and deposits | — | — | — | — | — | — | — | 
                                                883,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,646,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Inventories | — | — | — | — | — | — | — | 
                                                362,493,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,384,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                31,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Allowance for doubtful accounts | — | — | — | — | — | — | — | 
                                                -591,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -613,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | — | — | — | — | — | — | — | 
                                                1,445,712,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,229,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | ||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — | — | — | 
                                                20,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                21,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Property, plant and equipment | ||||||||||||||||||||||||
| Intangible assets | ||||||||||||||||||||||||
| Other | — | — | — | — | — | — | — | 
                                                45,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                45,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Intangible assets | — | — | — | — | — | — | — | 
                                                173,647,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                105,569,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | — | — | — | — | — | — | — | 
                                                6,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,986,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | ||||||||||||||||||||||||
| Non-current assets | — | — | — | — | — | — | — | 
                                                200,880,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                135,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Assets | — | — | — | — | — | — | — | 
                                                1,646,593,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,364,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | ||||||||||||||||||||||||
| Current liabilities | ||||||||||||||||||||||||
| Short-term borrowings | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                250,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Income taxes payable | — | — | — | — | — | — | — | 
                                                1,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | — | — | — | — | — | — | — | 
                                                152,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                581,193,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | ||||||||||||||||||||||||
| Asset retirement obligations | — | — | — | — | — | — | — | 
                                                7,617,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,615,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | — | — | — | — | — | — | — | 
                                                16,768,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                23,969,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | — | — | — | — | — | — | — | 
                                                169,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                605,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Provision for bonuses | — | — | — | — | — | — | — | 
                                                26,693,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                33,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Deferred tax liabilities | — | — | — | — | — | — | — | 
                                                789,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                824,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | ||||||||||||||||||||||||
| Share capital | — | — | — | — | — | — | — | 
                                                401,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                401,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Shareholders' equity | ||||||||||||||||||||||||
| Capital surplus | — | — | — | — | — | — | — | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retained earnings | — | — | — | — | — | — | — | 
                                                687,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,969,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Treasury shares | — | — | — | — | — | — | — | 
                                                -337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Shareholders' equity | — | — | — | — | — | — | — | 
                                                1,477,429,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,759,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | 
                                                687,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,477,429,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                401,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                687,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,477,429,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,969,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,969,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,759,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,759,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                401,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,102,642,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,892,709,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                389,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,892,709,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                401,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,102,642,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | — | — | — | — | — | — | — | 
                                                1,646,593,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,364,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — |