Sejfy was formerly part of the German Empire. In the German Empire, the place was called Seifen.
The place is now called Ryžovna and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Seifen | Austro-Hungary | Sankt Joachimsthal | before the Treaty of Saint-Germain |
| Sejfy | Czechoslovakia | Jáchymov | after the Treaty of Saint-Germain |
| Seifen | Czechoslovakia | Jáchymov | after the Treaty of Saint-Germain |
| Seifen | German Empire | Sankt Joachimsthal | 1938 |
| Ryžovna | Czechoslovakia | Jáchymov | 1945 |
| Ryžovna | Czechoslovakia | Karlovy Vary | 1992 |
| Ryžovna | Czech Republic | Karlovy Vary | 1993 |