Consolidated Balance Sheet
| Concept | As at 2024-03-31 | As at 2023-09-30 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | 
                                                2,307,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,233,057,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                716,560,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                692,159,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred tax assets | 
                                                53,764,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                216,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                169,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -89,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -94,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                1,442,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,479,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                359,553,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                300,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Work in process | 
                                                325,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                272,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                154,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                203,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                2,371,650,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,344,935,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | 
                                                1,551,441,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,496,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                883,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                883,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Construction in progress | 
                                                136,614,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                82,849,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Buildings and structures | 
                                                1,749,741,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,734,106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -1,291,269,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,256,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Buildings and structures, net | 
                                                458,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                477,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Machinery, equipment and vehicles | 
                                                91,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                57,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accumulated depreciation | 
                                                -53,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -46,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Machinery, equipment and vehicles, net | 
                                                37,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Intangible assets | 
                                                39,299,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                44,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Software | 
                                                34,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,769,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Distressed receivables | 
                                                19,682,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,478,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Deferred assets | ||
| Deferred assets | 
                                                14,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,573,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Business commencement expenses | 
                                                14,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,573,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                4,693,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,582,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                83,076,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts payable - other | 
                                                268,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                285,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                375,781,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                380,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                31,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                146,831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                230,584,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                6,489,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                1,224,380,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,247,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                1,321,150,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,507,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                19,981,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                1,555,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,749,952,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                214,700,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                220,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                2,780,213,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,997,773,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                1,836,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,514,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                530,450,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                530,450,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                438,968,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                438,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                882,976,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                563,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -15,986,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -17,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                20,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                20,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                55,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,342,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,913,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,584,792,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                4,693,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,582,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |