 Han Sen, a Chinese writer who was born in Berlin in 1925 but emigrated shortly after the "Machtergreifung" notes in his autobiography (entitled "Ein Chinese mit dem Kontrabass") that he knew this rule in his childhood; it must therefore have been current before 1933 at least in Berlin.The fast increasing popularity of the game in the twenties may be explained by the taste of the age.It was the early heyday of German Schlager.