John "Darkie" Smith trained a boxer who scored victories over six what?
Darkie Smith: John "Darkie" Smith (born 1942) is a British former boxer, now employed in boxing training and boxing matchmaking. Darkie Smith:  These fighters include European Heavyweight Champion Zeljko Mavrovic and future world champion Chris Eubank. Chris Eubank:  He held the WBO middleweight and super-middleweight titles, scoring victories over six world champions, and is ranked by BoxRec as the third best British super-middleweight boxer of all time.
i don't know