
Being a Good Tactician Requires Analysis & Pattern Recognition
I've noticed a trend of inexperienced players to believe that being a good tactician is primarily a matter of having a ton of tactical patterns of which you are familiar, somewhat as they think being a good opening player means memorizing a lot of opening lines.
While there is no doubt that knowing many, many tactical patterns, especially the basic ones (see A Different Approach to Studying Tactics and Tactical Sets and Goals), is both necessary and a prerequisite for being an excellent tactician, it is not sufficient. Every excellent tactician, using this knowledge as a basis, is also able to analyze unfamiliar patterns to discover if clever tactics exist and, if so, to find and play them. Otherwise they wouldn't be excellent tacticians - those who could would be better.
It is the marriage of analysis and pattern recognition or, more generically, intelligence and knowledge, that allows for superior tactical ability. Sure, players like Morphy, Fischer, and Kasparov had the same inherent abilities the day they were born as they did when they later ruled the chess world, but it was both the development of those abilities (with regards to chess, and not, say, physics, as it was for Einstein) and their eventual familiarity with patterns (via tactical study) to build upon that made them so dangerous.
I can illustrate some of this point through an example, which I have given to more than a hundred students:
Example 1:
All but the most basic beginners get this one correct: No, 1...Qxb5 is not safe because White can reply 2.Qh6 with the unstoppable threat of 3.Qg7#
This illustrates the important point that chess does have unstoppable threats (all the more so when two lower rated players meet), so simply moving without anticipating dangerous replies (checks, captures, and threats) and waiting to see what the opponent will do can lose the game instantly if the opponent makes a winning threat that cannot be met. So each move you have to make sure the opponent does not have such a reply, and I have dubbed this "Real Chess" while failing to attempt to do so I call "Hope Chess" (see my first ever online article The Secrets of Real Chess).
The other important point (besides that 1...Qxb5?? 2.Qh6 is an "unstoppable threat" and you can't just wait for those to happen) is that while this problem is easily solved by most experienced players just by pattern recognition, there are many short variation tactics that intermediate players might miss by pattern recognition, but could find by analysis. So when I play these players and they miss a tactic, they say afterwards that they "didn't see it" because they didn't recognize the pattern. But if you gave them my position as a "play and win" puzzle they would find it easily because 1) They know there is something there by the puzzle requirements and 2) They would not just rely on pattern recognition, but just use pattern recognition to aument (not replace) careful analysis.