Consolidated Balance Sheet
| Concept | As at 2023-09-30 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | 
                                                5,050,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,820,663,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                2,586,345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,342,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investment securities | 
                                                1,047,230,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                991,360,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                265,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                255,839,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -5,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,621,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                4,794,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,887,434,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts receivable - trade | 
                                                1,531,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,920,142,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                97,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                92,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                92,433,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                65,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                8,580,734,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,653,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                2,390,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,402,498,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings, net | 
                                                175,021,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                175,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                1,677,601,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,677,601,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other, net | 
                                                354,998,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                370,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Own-used assets | ||
| Other | — | — | 
| Intangible assets | ||
| Intangible assets | 
                                                73,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Deferred assets | ||
| Deferred assets | 
                                                5,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Bond issuance costs | 
                                                5,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                13,636,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,480,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Notes and accounts payable - trade | 
                                                806,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                999,052,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Short-term borrowings | 
                                                200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                93,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                98,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                68,909,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                102,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                174,222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                127,249,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                2,122,357,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,387,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Bonds payable | 
                                                500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                288,294,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                165,231,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                847,377,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                726,967,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                2,969,735,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,114,279,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                10,103,367,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,045,276,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                1,204,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,204,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                819,054,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                819,054,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                8,124,624,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,066,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -45,211,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -45,211,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                563,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                320,455,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                563,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                320,455,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                10,666,459,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,365,732,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                13,636,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,480,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |