Schlage was a professional insurance agent. Due to an injury in the First World War, he was from 1917 to 1918 in the hospital. After representation Helmut Wietecks be held in Berlin chess master before the Second World War, a time in Africa, and is, amongst others, have been working as a chess teacher.
In 1940 he died of a stroke. His grave is located in Neukölln on the cemetery of the St. Thomas community.
Suggest worked intensively on chess theory. He drew on his extensive chess library.
Schlage became a member of the Berlin Chess Club. In 1910 he took on the main tournament B of the German Chess Federation in Hamburg, but did not qualify for the winners group. Three times he participated in the German championships. In 1921, he finished in Hamburg Platz 3, 1922 in Bad Oeynhausen 3rd to 5th, 1935 in Aachen, he was less successful.
Between 1920 and 1934 he participated five times in the Berlin Championships, 1921 and 1926, he was here first. Six times he was called to the national team.
His best historical Elo rating was 2517th This he achieved in August 1923.
Suggest taught and encouraged many young German players, such as Klaus boy, Wolfgang Unzicker, Edith Keller. In 1935, he became coach of the United Kingdom of the German Chess Federation. Together with Alekhine and Bogolyubov he prepared the German team before the (unofficial ) Chess Olympiad 1936 in Munich. Then he assisted Kurt Richter at its zweibändigem tournament book Chess Olympics Munich 1936.
In 1979, the African Republic of Mali issued a chess stamp with the portrait Willi shock. The stamp is part of a series "Grandmaster of Chess ", which shows him next to the more famous Alekhine, Bogolyubov and Janowski.