|Full name||Mieczysław Chwojnik|
Ruzhany, Russian Empire
Mieczysław (Mendel) Chwojnik, later known as Dr. Menachem Oren (Hebrew: מנחם אורן; 1903, Ruzhany, Russian Empire (now Belarus) - December 1962, Tel Aviv, Israel) was a Belarusian-born Israeli chess master and mathematician.
Chwojnik was the strongest Cracovian chess player in 1920s; thrice winner of the Cracow championships (1919, 1925, 1926). He won the Nowy Dziennik tournament in Cracow in 1926.
He played in two Polish championships. In 1926, he tied for 8-9th in Warsaw (1st POL-ch). The event was won by Dawid Przepiórka. In 1927, he tied for 5-7th in Łódź (2nd POL-ch). The event was won by Akiba Rubinstein. In 1928, he represented Poland on fourth board at the 2nd Chess Olympiad in The Hague (+4 -3 =4), and won team bronze medal.
He left Cracow for Rivne, Volhynia (then Poland), in the 1930s. He won in the Rivne City championship in 1938. During World War II, he lived in the Soviet Union. After the war, he returned to Poland in 1945/46, and settled in Lower Silesia.
In 1949, Chwojnik emigrated, via Czechoslovakia and Austria, to Israel, where he had changed name to Menachem Oren. In 1951, he won the Israeli championship and the Tel Aviv City championship. In 1952, he won again the Tel Aviv City championship.
He played thrice for Israel in Chess Olympiads: at second board (+6 -4 =3) at Helsinki 1952, third board (+7 -2 =3) at Amsterdam 1954, and fourth board (+2 -2 =4) at Moscow 1956.