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 | 
                                                1,094,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                975,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts receivable - trade | 
                                                2,204,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,798,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Contract assets | 
                                                1,395,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                367,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Merchandise and finished goods | 
                                                663,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                521,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                438,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                360,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                225,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                6,682,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,745,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                1,820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,914,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                863,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                891,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investment securities | 
                                                73,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                37,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                45,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                492,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                538,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -27,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Buildings and structures | 
                                                1,215,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -756,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -735,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated impairment | 
                                                -90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -92,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings and structures, net | 
                                                369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                392,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Machinery, equipment and vehicles | 
                                                414,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                414,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -411,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -407,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated impairment | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Machinery, equipment and vehicles, net | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | 
                                                773,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Other | 
                                                183,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other intangible assets | ||
| Intangible assets | 
                                                183,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Retirement benefit asset | 
                                                277,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                280,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                8,503,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,659,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                800,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Notes and accounts payable - trade | 
                                                1,156,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,907,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                89,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                342,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for product warranties | 
                                                3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,024,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                919,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                3,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,234,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Deferred tax liabilities | 
                                                111,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                81,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                246,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                267,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                80,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                80,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                3,391,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,502,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                5,082,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                523,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                523,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                4,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                29,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                30,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                5,111,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,157,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                8,503,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,659,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments | ||
| Remeasurements of defined benefit plans | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |