I think I've had dozens of repertoires over the years. The last one I wrote about in these pages was my Knightmare Repertoire (built around mirror systems with e4, Nc3, and Nf3 as White and e5, Nc6, and Nf6 as Black), which bears some connection to my current approach. I also documented my Caveman or Left Hook Repertoire for White (which included the Urusov Gambit, Two Knights with d4, Steinitz-Sveshnikov Attack, Evans Gambit, Modern Horowitz Max Lange, Anti-Petroff with d4, Left Hook Grand Prix, Left Hook Austrian, Wing Gambit French, Caveman Caro-Kann, and Saemisch Attack vs. the Alekhine) and various unusual systems as Black (including a universal 1...Nc6 system and an early d6 system that included the Philidor, Panther, and Janowski Indian or Janowski's Brother). Along the way I've also flirted with various completely different ideas, including the d-pawn repertoire built around the Barry Attack and Colle-Zukertort as laid out by Aaron Summerscale in A Killer Chess Opening Repertoire and recently updated by Richard Palliser in Starting Out: D-pawn Attacks.
I really don't know how other players go about constructing their repertoires, and it might make for a good interview question -- or a question for readers. How do you go about it? Steve Giddins once devoted an entire book to the subject (How to Build Your Chess Opening Repertoire). Perhaps most players simply pick up one of the many books on the market offering a ready-made repertoire and read it carefully from cover to cover. While I love repertoire books, I rarely find myself adopting more than one or two lines from any of them. Most book repertoires are simply not coherent enough for my taste. Perhaps some players work with coaches to create a coherent system, or perhaps they just let things fall into place over time, with new acquisitions coming on organically along the way.
It's my desire for coherence that drives my changes, and I am rather dogmatic in my approach. I want to have a coherent system, and so a change in any opening line will inevitably trigger a cascade of adjustments throughout my repertoire. The Knightmare Repertoire came about because I found myself playing the Tango (1.d4 Nf6 2.c4 Nc6 3.Nc3 e5) and the Berlin Variation of the Ruy Lopez (1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6), and soon it just seemed natural to adopt the Four Knights, the Two Knights French, and so on down the line until I was playing practically every system where you move your two Knights and your e-pawn in the first three or four moves. A similar process created the Caveman repertoire for White, which arose out of my desire to develop a dark square attacking formation (generally centered around an e5 advance).
My current system began much the same way. I had been building up an Open Game system with 1.e4 e5 as Black when I started playing lines with a kingside fianchetto, especially the Three Knights (1.e4 e5 2.Nf3 Nc6 3.Nc3 g6). Meanwhile, I was struggling to find a good line against the Italian Game that did not involve too much study or any gambits, and just around that time I happened to annotate the game Weeramantry-Bisguier, USATE 2008 which suggested that a kingside fianchetto might work more universally than I had imagined possible. I decided to see how far I could take the idea and started researching other lines where Black plays an early g6 advance in the Open Games, including the Smyslov Variation of the Ruy Lopez (1.e4 e5 2.Nf3 Nc6 3.Bb5 g6). I started playing it in blitz and really enjoyed the types of positions I was getting in those lines, which reminded me of my most positive experiences with the King's Indian Defense. I had given up the KID years ago when it just seemed too difficult to keep up with the theory. But maybe a modified King's Indian system was possible, one that did not involve too much study? As I studied the Open Games with g6, the KID seemed inevitable -- and a natural addition since some KID lines could arise via the Open Games (such as by 1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Nxd4 g6 5.c4, which heads toward an interesting line that could arise via the Classical KID).
With the KID and the Open Games with g6 on board, I soon found myself looking at other lines with a kingside fianchetto, such as the Glek System of the Four Knights (1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.g3), the Vienna with g3 (1.e4 e5 2.Nc3 Nf6/Nc6 3.g3), the Closed Sicilian or an Open system with g3 (depending on Black's set-up), and an anti-Pirc system with g3. It all seemed so natural.
Of course, there were some complications. For one thing, in order to avoid taking on the whole King's Indian, I decided it made sense to keep the Tango against any line where White did not commit to Nf3. That way I could avoid the Four Pawns Attack, the Saemisch, and a whole host of other White systems. Keeping the Tango also allowed me to focus generally on lines where Black plays an ...e5 advance, as in the Classical and the Fianchetto (with Nbd7 and e5). And the Tango made sense because I was also drawn to the Two Knights French and Two Knights Caro-Kann, which were practically like reversed Tango systems in some lines (especially where Black plays a d4 advance).
There were many other adjustments, of course, too numerous to mention -- and I am still trying to work out all the transposition tricks and marginal lines. Here is the broad outline of what I have so far and what books I've been looking at to help me organize my study (suggestions for additional lines and useful books or articles are most welcome):
Smyslov Variation of the Ruy Lopez (1.e4 e5 2.Nf3 Nc6 3.Bb5 g6)
- Offbeat Spanish by Glenn Flear
- "The Solid but Tricky Fianchetto Spanish" by Glenn Flear in SOS #2.
- "Radulski's Ruy Lopez" in SOS #3
- Opening for White According to Anand, Volume 1, by Alexander Khalifman
- Beating the Ruy Lopez with the Fianchetto Variation by Andrew Soltis
- Italian Game and Evans Gambit by Jan Pinski
- "Livening Up the Three Knights and Scotch" by John Emms in Dangerous Weapons: 1.e4 e5
- An Unbeatable White Repertoire after 1.e4 e5 2.Nf3 by Larry Evans and Ken Smith
- "Centre Game Revealed, Part III" by Andrew Greet in Dangerous Weapons: 1.e4 e5
- Play 1.e4 e5 by Nigel Davies
- Tango! by Richard Palliser
- The Black Knights' Tango by Georgi Orlov
- Joel Benjamin's Opening Shortcuts columns at Jeremy Silman's site
- Opening for White According to Kramnik, 1.Nf3: Modern Lines in the King's Indian Defence by Alexander Khalifman
- Kasparov on the King's Indian, by Gary Kasparov and Raymond Keene
- Kasparov's Chess Openings by Otto Borik
- Winning with the King's Indian by Eduard Gufeld
- The Art of the King's Indian by Eduard Gufeld
- Miguel Najdorf: King of the King's Indian by Nikolai Minev
- The New Classical King's Indian by John Nunn and Graham Burgess
- An Active Repertoire for Black by Drazen Marovic
- English ...e5 by Alex Raetsky and Maxim Chetverik
- Gambit Guide to the English 1...e5 by Carsten Hansen
- Beating the Flank Openings by Vassilios Kotronias
Paulsen-Mieses Vienna or Glek Four Knights (1.e4 e5 2.Nc3 Nf6/Nc6 3.g3 or 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.g3)
- A Startling Chess Opening Repertoire by Chris Baker
- "Russian Roulette" by Viktor Moskalenko in The Flexible French
- A Startling Chess Opening Repertoire by Chris Baker