Consolidated Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | 
                                                18,597,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,239,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                1,979,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investment securities | 
                                                1,093,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,207,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments in capital | 
                                                101,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                208,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                830,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                842,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                4,981,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,281,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes receivable - trade | 
                                                68,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                7,670,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,804,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - other | 
                                                403,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                406,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                2,028,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,937,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Supplies | 
                                                242,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                226,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Inventories | 
                                                4,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,111,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                19,633,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                16,360,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,863,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                6,107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,008,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets, net | 
                                                115,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                331,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                271,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other, net | 
                                                1,398,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,272,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Buildings and structures | — | — | 
| Buildings and structures, net | 
                                                3,330,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,167,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Machinery, equipment and vehicles | — | — | 
| Machinery, equipment and vehicles, net | 
                                                5,075,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,996,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Leased assets | — | — | 
| Other | — | — | 
| Intangible assets | ||
| Other intangible assets | ||
| Other | 
                                                124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                257,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                248,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Software | 
                                                133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                131,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Distressed receivables | 
                                                8,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit asset | 
                                                48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                38,230,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,901,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                4,234,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,802,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                2,931,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                269,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts payable - other | 
                                                844,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                83,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                1,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                526,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                567,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,030,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,459,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                15,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,007,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses for directors (and other officers) | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                35,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                939,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,443,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax liabilities | 
                                                213,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                2,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,844,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Lease liabilities | 
                                                52,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for retirement benefits for directors (and other officers) | 
                                                9,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                82,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                4,005,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                19,303,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                11,198,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                2,163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                1,888,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,882,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                7,192,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,113,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -46,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -55,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                2,702,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,087,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                164,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                262,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                2,169,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,433,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-controlling interests | 
                                                5,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,982,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                18,926,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                38,230,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,901,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments | ||
| Remeasurements of defined benefit plans | 
                                                369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                391,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |