Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | 
                                                3,666,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,221,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                988,103,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                884,562,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Buildings and structures | — | — | 
| Buildings and structures, net | 
                                                1,988,115,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,819,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Other | — | — | 
| Other, net | 
                                                687,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                513,222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | 
                                                2,675,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,333,103,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                3,487,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Investments and other assets | ||
| Current assets | ||
| Cash and deposits | 
                                                9,688,963,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,844,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                479,378,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                428,642,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                240,121,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                174,846,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                459,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                391,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                10,868,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,839,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                14,535,156,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,060,907,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Long-term borrowings | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for retirement benefits for directors (and other officers) | 
                                                536,338,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                517,368,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                197,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                214,201,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                734,219,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                742,017,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Notes and accounts payable - trade | 
                                                1,394,117,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                670,320,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                454,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                104,401,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                41,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                124,992,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                2,048,970,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,629,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                3,939,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,529,643,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                4,673,467,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,271,660,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                9,859,674,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,788,021,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                361,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                336,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                389,420,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                364,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                9,109,893,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,088,460,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -953,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -712,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                2,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                2,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                9,861,688,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,789,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                14,535,156,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,060,907,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |