Portisch: My Secrets in the Ruy Lopez Holz Vigorito is well known for

Vigorito is well known for his opening expertise

Jerzy Konikowski is a FIDE master and is known as the author of a large number of excellent opening books

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The point is that the authors recommend to answer 1

Winning in 15 Moves or Less: Chess Tactics

Portisch: My Secrets in the Ruy Lopez Holz Vigorito is well known forIt's major news when a legendary player reveals his opening secrets. And when he has rarely written about his games or preparation methods, and was famous for meticulous, ahead of his time opening analysis, it makes it a true publishing event. Yet that is what eight time world championship candidate Lajos Portisch has done. In this book, he opens his extensive opening files and presents the most important games and unused novelties in the Ruy Lopez