When it comes to tactics training what is the best approach to optimize results? I've recently started only doing really hard puzzles, the only immediate change is it obviously take me a lot longer and end up maybe doing around 10-20 per day. Is it quality or quantity that's more important? Also as a side question I keep hearing that playing blindfold chess is bad for you for some reason? Can someone explain why I keep hearing that?
I'm assuming your aim in practicing tactics is to improve your game performance. In that case, I would recommend you treat each problem not as a puzzle, but as a real game situation, because your goal is to be able to spot tactics OTB, without knowing whether or not a tactical shot exists or not.
Thus, you should apply the thinking process you would use in a real game to the puzzle, and just try to play the move you would in a real game.
This means that you would, after a quick evaluation of the initial position, look for (1) Forcing moves, checks/caps/threats, (2) logical, positionally sound options that increase your activity/decrease opponent's activity. Then, you should calculate and evaluate these candidate moves one by one, and determine which one is the best. This is how you would play in a real game, and thus your tactical training should be like this.
If you can't spot the tactic (get the problem wrong), then you know that something is wrong with your thinking process, and you can correct it immediately. For example, if you spotted all the appropriate candidate moves, but, after calculation/evaluation, didn't find a winner, and thus settled for a "positional" move, then you know that there's an issue in your calculation; maybe you didn't remember to find all candidate moves at every move, and thus missed something. Or perhaps you couldn't visualize a long sequence, and now you know you have to get better at this.
This is assuming you know how to improve every aspect of your thinking process. There are many free online resources, particularly youtube, that tell you how to train to improve certain things.
I think that 10-20 difficult puzzles is plenty, as long as you apply your thinking process to each, and remember to diagnose/improve your thinking process at the end of each puzzle. Also, remember that in a real game, you have around 3 minutes per move. In critical situations, you may use more, but try not to use more than x minutes for a move, if you not spend more than x minutes on the position in a game.
Also, playing blindfold chess is not bad. Blindfold chess is one way to improve your visualization skills, which is crucial for calculation.
I am a USCF expert rated player.
Use a book on tactics. This will help you recognize tactical patterns and subconsciously organize them into themes. A good book will also provide an appropriate amount of puzzles to each theme. Tactical themes usually occur with each other, and capitalizing on that usually involves a sacrifice, and the variations leading is called a combination. A book that fits nicely with that would be "Chess Tactics for Champions" for Susan Polgar.
Solve puzzles. Other than the puzzles you'd find in a book, solve lots and lots of puzzles. Solving online puzzles is a free and engaging way.
Play blitz. Blitz games are all about tactics and so you get to play a whole game that is based on a tactical and often sacrificial style. And what is good about blitz especially for tactics is that if your sacrifice is not sound, but good enough to catch your opponent off guard and force him to defend correctly, you would usually win on time! Blitz is all about tactics.
I find that one of the things missing in tactics training is concentrated, thematic study, i.e., you try and solve a few dozen tactical problems with the same theme - Discovered Attack, The Mill, etc. Often there is a theme you might not be that familiar with and it shows when you try and solve tactical puzzles. Even though it might seem to point you in the right direction to solve the puzzle, that's not really the point. The point is to get used to seeing these themes in action so you can quickly recognize them in your games or when solving difficult tactical puzzles in earnest. In this regard, I use Renko's Intensive Course Tactics for thematic solving practice.
- Thematic Study to understand all the different tactical nuances
- Master tactics problem-solving at 70+ percent success rate
Blitz makes you lazy in calculation, so be careful. You'll "get away" with lots of bad tactics in blitz that you will pay for in real points in real games. You can generally spend 5 minutes on any position in a real game - not so in blitz.
Also, it might be worthwhile to keep a sheet of paper handy and note what "theme" you missed when you get a problem wrong. For example, let's say you failed to see a discovered check - write it down. Be honest. This will identify themes you are weak at.