Quarterly Statement Of Cash Flows
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Quarterly statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                -67,983,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -140,153,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                46,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -2,938,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -70,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -143,071,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -2,957,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -18,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -16,271,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | 
                                                21,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                19,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                342,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                -10,723,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -81,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -133,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                764,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                845,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                978,046,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,111,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |