Major Shareholders
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|
| Major shareholders | |||||||||||
| Major shareholders | |||||||||||
| Name | 
                                                巴川コーポレーション取引先持株会
                                                
                                             | 
                                                三井化学㈱
                                                
                                             | 
                                                ㈱井上ホールディングス
                                                
                                             | 
                                                東栄不動産㈱
                                                
                                             | 
                                                鈴与㈱
                                                
                                             | 
                                                ㈱三井住友銀行
                                                
                                             | 
                                                栄紙業㈱
                                                
                                             | — | 
                                                TOPPANホールディングス㈱
                                                
                                             | 
                                                東紙業㈱
                                                
                                             | 
                                                三弘㈱
                                                
                                             | 
| Address | 
                                                静岡県静岡市駿河区用宗巴町3-1
                                                
                                             | 
                                                東京都中央区八重洲2-2-1
                                                
                                             | 
                                                東京都新宿区若宮町25
                                                
                                             | 
                                                東京都中央区京橋1-1-9
                                                
                                             | 
                                                静岡県静岡市清水区入船町11-1
                                                
                                             | 
                                                東京都千代田区丸の内1-1-2
                                                
                                             | 
                                                東京都中央区京橋1-1-9
                                                
                                             | — | 
                                                東京都台東区台東1-5-1
                                                
                                             | 
                                                東京都中央区京橋1-1-9
                                                
                                             | 
                                                東京都中央区京橋1-1-9
                                                
                                             | 
| Number of shares held | 
                                                528,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                487,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                631,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                295,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                498,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                275,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                700,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                5,470,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,139,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                463,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                448,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Shareholding ratio (excluding treasury shares) | 
                                                0.0524
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0483
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0626
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0293
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0494
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0273
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0694
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.5425
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.1130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0459
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0444
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |