Consolidated Statement Of Cash Flows
| Concept | 2023-07-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-06-30 | 2022-07-01 to 2022-12-31 | As at 2022-12-31 | As at 2022-06-30 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                -86,486,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -178,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -28,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -4,916,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -4,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -91,907,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -183,778,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -128,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -6,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -142,005,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | 
                                                52,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                85,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Loan advances | 
                                                -549,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from collection of loans receivable | 
                                                65,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -2,168,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from short-term borrowings | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | 
                                                -30,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of short-term borrowings | 
                                                -100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -34,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -22,529,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -18,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -30,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -20,483,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -59,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -2,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -6,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -254,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -246,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                453,964,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                708,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                418,005,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                639,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |