A German MC player, born in Saarbrucken in 1949. He rose rapidly thorugh the Junior ranks, first in Germany and then on the World Stage, winning the German Junior Championship from 1960-1966 and becoming World Junior Champion in 1965. However, he was unable to make the transition to Senior MC. He arrived at the 1967 World Championship full of hope and arrogance. Unfortunately he was defeated 10-0 in the first round.
He never recovered from this severe blow to his pride and ego and never got beyond the second round until his retirement in 1972 in a blaze of sour grapes directed towards the MC glory his arrogance led him to believe would automatically be his. The five years betwen then and his tragic suicide are a sad tale of a man destroyed by over-optimism and unrealistic expectation. In 1976 in a final insult to the MC authorities, he invented Groenback's Adjustment Variant to show the game as the absurd scam he had convinced himself it was. In a final blow, it rapidly beame a popular and widely accepted variant.