Karl Mathias Berndtsson Kullberg (16 March 1892 – 29 September 1943) was a Swedish chess master who was born and died in Göteborg.
He won at Copenhagen 1916,[1] and lost a match for the Swedish Chess Championship to Gustaf Nyholm (1½–3½) in 1917.
He took 14th at Göteborg 1920 (Paul Johner won),[2] won Nordic Chess Championship at Oslo 1928,[3] and took 6th at Örebro 1935 (Alexander Alekhine won).
[4] Berndtsson played for Sweden in three Chess Olympiads: and won team bronze medal in 1933.
[5] This biographical article relating to a Swedish chess figure is a stub.