Mezue ahịrịokwu na-esonụ: Ọnọdụ a sitere na Egwuregwu 17 nke 1978 World Championship n'etiti Viktor Korchnoi, onye na-ama aka, na Onye mmeri ụwa, Anatoly Karpov. Karpov, na-egwu Black, na-eyi onye na-esote ya egwu na 39...Rc1#. Korchnoi nwere ike igbochi nke a site na ịkwaga g-pawn ya (mana ọ bụghị h-pawn n'ihi na 39.h3 ma ọ bụ h4 na-eduga na 39...Rc1+ 40.Kh2 Nf1+ 41.Kg1 Nfg3+ 42.Kh2 Rh1#), na-enye square mgbapụ maka eze ya. N'ime nsogbu oge siri ike, Korchnoi gbara egwu wee kwụsị mgbe 39...Nf3+ na chessmate a manyere mgbe 40. gxf3 Rg6+ 41. Kh1 Nf2# ma ọ bụ 40.Kh1 Nf2#. Karpov gara n'ihu merie egwuregwu ahụ ma mesịa merie Korchnoi ọzọ na 1981 na "
Ogbugbu e gburu ndị mmadụ na Merano".