Viktor Kortschnoj (1931-2016) was born in Leningrad, USSR (now Saint Petersburg, Russia).
A four-time Soviet Champion and two-time World Championship Challenger (1978, 1981), Kortschnoj is universally considered one of the greatest chess players never to become World Champion. Other players in this category could include Akiba Rubinstein, Reuben Fine, Paul Keres, David Bronstein, and Vassily Ivanchuk.
While I haven’t read those volumes, I did work through his Practical Rook Endings. Highly recommended, and well worth the effort expended. I wouldn’t be surprised if Kortschnoj’s boast that the book will raise your rating 100 points was true. Considering it’s only about 100 pages, this is great value!
Let’s take a look at an instructive miniature “Viktor the Terrible” won against International Master Stefano Tatai (1938-2017). Tatai was 12 times Champion of Italy between 1962 and 1994.
A series of small errors has made White’s situation critical. Black to play.