This theoretically solid opening repertoire for White, based on playing 5.d4 in the main line of the Ruy Lopez (1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6), gives you a great way to bamboozle your opponent, who is probably unprepared for this variation and its many pitfalls. Black can easily go wrong within the next few moves and quickly lose material or succumb to a crushing attack. White is poised to castle and engage in battle; Black's king is vulnerable in the center and may find no relief on the kingside as White develops pieces to powerful outposts and forces pawn moves that allow attackers to pour in.This variation is named after Scottish-American master George Mackenzie, who popularized it in the nineteenth century. He was undefeated with it, overwhelming some top masters of that day.Elite competitors from many eras have played the Mackenzie Variation, including Morphy, Lasker, Alekhine, Tal, Short, and Cramling. In recent years, grandmasters such as Jones, Kosteniuk, and Yoo have used it to great effect, especially in rapid and blitz games, when opponents have little time to find a sound defense.A final chapter shows you how to meet the popular Berlin Defense (3...Nf6) with a Mackenzie-style thrust, 4.d4. Again, many difficult decisions and tricky positions await the unwary Black player. As well as variations and advice, this book contains 57 model games with key annotations, from Morphy in 1858 through to a dozen examples from the 2020s.The author, David Gertler (USA), has held the FIDE Master title since 1985. A former Chess Life magazine staff member, he has written many published articles and game analyses. Highlights of his half century of tournament competition range from being co-champion of the 1982 US Junior Open to twice finishing joint-second in the US Senior Open. David has played the Mackenzie Variation more than 1,000 times (with great success) in classical, rapid, and blitz games."In this lucid and well-researched book, David Gertler shows you how to make the Mackenzie Variation a formidable weapon." - Stuart Rachels, former US champion and author of The Best I Saw in Chess