Shareholdings
| Concept | 
                                    
                                        As at 2025-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                        
|---|---|---|
| Shareholdings | ||
| Reporting company | ||
| Details of specified investment shares held for purposes other than pure investment | ||
| Issue | 
                                        
                                             
                                                ダイワボウホールディングス㈱
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Number of shares | 
                                        
                                             
                                                30,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                30,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Carrying amount | 
                                        
                                             
                                                75,855,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                77,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                        
                                             
                                                主要な仕入先であり、良好な関係の維持・拡大を図る目的で保有しております。定量的な保有効果は秘密保持の観点から記載いたしませんが、保有の便益と当社資本コストの比較により経済合理性を検証しております。
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    — |