Hi there! First of all, congratulations on beating a player rated 1688, that’s a great achievement! It’s great that you’re taking on a challenge and playing against your teacher who is a former 2300 player.

If you’re looking to improve your opening play, I would suggest focusing on one or two openings that you feel comfortable with and learning the main ideas behind them. You don’t need to memorize every single move, but it’s important to understand the key concepts and typical pawn structures for each opening.

There are many online resources available for learning chess theory and openings, such as chess.com’s lessons, YouTube videos, and online courses like Chessable. I would recommend starting with beginner-level material and gradually working your way up as you improve.

In terms of specific openings to learn, I would recommend some of these:

1. Sicilian Defense: 1.e4 c5 – This is a very aggressive and tactical opening for Black, which can lead to very sharp and complicated positions. It’s one of the most popular openings at all levels of play.
2. French Defense: 1.e4 e6 – This is a solid and positional opening for Black, which aims to control the center with the pawn on d5. It’s a good choice for players who prefer a more strategic and less tactical game.
3. Caro-Kann Defense: 1.e4 c6 – This is another solid and positional opening for Black, which also aims to control the center with the pawn on d5. It’s a good choice for players who want to avoid some of the sharper lines of the Sicilian Defense.
4. Ruy Lopez: 1.e4 e5 2.Nf3 Nc6 3.Bb5 – This is a very popular and well-studied opening for White, which aims to control the center and put pressure on Black’s e5-pawn. It leads to a wide variety of positions and is considered one of the most important openings in chess theory.
5. King’s Indian Defense: 1.d4 Nf6 2.c4 g6 – This is a very aggressive and dynamic opening for Black, which aims to attack White’s center with pieces and pawns. It can lead to very complicated positions and is a good choice for players who enjoy a tactical game.

But as Bruce Lee says: “I fear not the man who has practiced 10,000 kicks once, but I fear the man who has practiced one kick 10,000 times.” So instead of learning every opening, just focus on improving your game using a few specific openings.

Additionally, it’s important to practice your tactics and calculation skills. Chess.com has many tactics puzzles and training exercises that can help you improve in this area.

Trading away pieces, especially the queen, can be a useful tactic against higher rated opponents in order to simplify the position and enter an endgame. This can be particularly effective when the higher-rated opponent has a more complex position or more active pieces, as simplification can reduce their advantage. However, it’s important to be careful when trading pieces, as making careless or “stupid” trades can easily backfire and leave you in a worse position. Before making a trade, it’s important to evaluate the position and consider whether the trade will benefit you in the long run. Some factors to consider include:

1. Material: Make sure you’re not giving away too much material in the trade. Trading a knight or bishop for a pawn or two might not be worth it, but trading a rook for a queen or a minor piece and a pawn might be.
2. Positional factors: Consider whether the trade will improve your position in terms of pawn structure, space, or piece activity. If the trade will leave you with a cramped or passive position, it may not be worth it.
3. Tactical factors: Look for any potential tactics or combinations that might arise from the trade. If the trade allows you to launch a strong attack or win material, it might be worth considering.

In general, it’s important to approach trades strategically and not just trade pieces for the sake of simplifying the position. Even in the endgame, where material is often more valuable, it’s important to keep an eye on other positional and tactical factors and not make careless mistakes. By being strategic and thoughtful about your trades, you can use simplification as a tool to level the playing field against higher rated opponents and increase your chances of success.

Most importantly, don’t get too caught up in the opening. Remember that chess is a game of strategy and not just memorization. Focus on developing your pieces, controlling the center of the board, and creating a plan based on the position.

Good luck with your match against your teacher, and most importantly, have fun and enjoy the game!