It is a rarity and as it should be. Decades of top basketball in Groningen resulted in only two back numbers that may never be worn again at Donar. The jersey with number ten, which has a permanent place in the Groningen basketball temple, belongs to Martin de Vries, also known as Mister Donar. In the years 1979 to 1983 and 1986 to 1990, the Groningen player was one of the icons of the northern basketball pride.