Preparations of an amateur V: The importance of checking your opponent's games

Having just finished with 4/8 in Split Open (including a first ever draw vs a 2000+ player), it is easy to bask in the personal "glory" of doing a lot better than rating would suggest. However, there were plenty of mistakes; 2/6 vs players with an average rating of 1900 should have been 3,5/6 - at least.

One win brought home the importance of just checking your opponent's game history. Not necessarily to prepare for hours on end, but just to make sure you are prepared if he comes along with a rare line.

This was the case in the following game, where I ended up with a nice win with Black. One important reason was how I handled the opening.

After this opening, White has two passed pawns on the queen side, are still a pawn up after the b4 sacrifice, can castle in two moves and only has one weak square: d6. White, on the other hand, has a very weak pawn on c3 and a bunch of weak squares on the queen side/and three in the centre; c3, c4 and d3.

As the game went on, White had a fine king side attack that included a classic Bxh7+ sacrifice, and Black somewhat unnecessary gave that material back in order to exhange queens and relieve the tension (but keeping the early extra pawn). Then, the pawns on the queenside became a major headache for White - so the opening exchanges brought some important imbalances that played a decisive part in the end game. 

A nice win, of course, but very much a game where I realized the practical importance of being prepared. Had I met 4. b4 without knowing the most important lines in advance, I would probably have played worse.