Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                2,797,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,392,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes receivable - trade | 
                                                223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                406,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                3,932,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,165,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Merchandise and finished goods | 
                                                5,457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,925,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                3,882,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,759,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Raw materials and supplies | 
                                                2,349,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                650,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                617,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                23,229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,925,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Buildings and structures | — | — | 
| Buildings and structures, net | 
                                                2,634,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,731,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Machinery, equipment and vehicles | — | — | 
| Machinery, equipment and vehicles, net | 
                                                4,813,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,880,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                5,852,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,869,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets | — | — | 
| Leased assets, net | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                394,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                408,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | 
                                                13,807,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,014,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Intangible assets | 
                                                256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                164,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Investment securities | 
                                                1,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,799,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                924,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                247,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit asset | 
                                                2,020,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,956,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -25,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -25,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                5,039,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,902,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                19,104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,081,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                42,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,006,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Long-term borrowings | 
                                                5,775,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,891,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                4,621,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,408,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for retirement benefits for directors (and other officers) | 
                                                8,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                118,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                10,551,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,455,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Short-term borrowings | 
                                                4,821,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,371,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                2,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                75,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                237,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of bonds payable | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accrued expenses | 
                                                986,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                988,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                238,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                613,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                740,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                495,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                9,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,837,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                20,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,293,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                20,798,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,345,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                8,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                8,164,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,164,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                4,573,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                1,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,368,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                379,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                289,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                240,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                22,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,713,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                42,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,006,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments | ||
| Remeasurements of defined benefit plans | 
                                                769,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                859,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |