Consolidated Balance Sheet
| Concept | As at 2024-09-30 | As at 2024-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Current assets | ||
| Cash and deposits | 
                                                710,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,059,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts receivable - trade | 
                                                2,596,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,848,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Contract assets | 
                                                1,688,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Merchandise and finished goods | 
                                                547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                401,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                310,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                289,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                226,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                6,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,717,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                786,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                801,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Buildings and structures | 
                                                1,294,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -818,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated impairment | 
                                                -103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings and structures, net | 
                                                372,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                380,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Machinery, equipment and vehicles | 
                                                318,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                311,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated impairment | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Machinery, equipment and vehicles, net | 
                                                7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Other intangible assets | ||
| Other | 
                                                147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                975,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investment securities | 
                                                90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                65,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                477,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                491,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Retirement benefit asset | 
                                                291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                1,839,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,943,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                8,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Notes and accounts payable - trade | 
                                                1,587,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,226,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Short-term borrowings | 
                                                500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                43,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                110,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                307,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                492,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for product warranties | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,099,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                3,374,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Deferred tax liabilities | 
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                58,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                53,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                246,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                230,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                158,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                3,621,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,184,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                4,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,431,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                523,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                523,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                3,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,411,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                42,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                42,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                4,972,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,476,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                8,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |