Shareholdings
| Concept | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2024-01-31 | As at 2024-01-31 | As at 2024-01-31 | As at 2024-01-31 | As at 2024-01-31 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Shareholdings | ||||||||||
| Reporting company | ||||||||||
| Details of specified investment shares held for purposes other than pure investment | ||||||||||
| Issue | 
                                                テクノプロ・ホールディングス㈱
                                                
                                             | 
                                                ㈱メイテックグループホールディングス
                                                
                                             | 
                                                ㈱アビスト
                                                
                                             | 
                                                ㈱コプロ・ホールディングス
                                                
                                             | 
                                                ㈱アルプス技研
                                                
                                             | — | — | — | — | — | 
| Number of shares | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                200
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                200
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Carrying amount | 
                                                310,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                332,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                293,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                288,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                                業界動向等の情報収集のため
                                                
                                             | 
                                                業界動向等の情報収集のため
                                                
                                             | 
                                                業界動向等の情報収集のため
                                                
                                             | 
                                                業界動向等の情報収集のため
                                                
                                             | 
                                                業界動向等の情報収集のため
                                                
                                             | — | — | — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | — | — | — | — | — |