Opening explorer
An opening explorer is a tool that shows, for any position reached from the start, which moves players have chosen in past games and how often each move led to a win, draw or loss.
Also called: explorer
An opening explorer sits on top of a large collection of games. You play moves on a board, and for each position it lists the continuations that were tried, how popular each one was, and the results. Some explorers let you filter by rating range or by the type of game, so you can see what players like you actually do, not only what masters play. For a club player, it is a way to learn the most common paths, to find where your opponent left known theory, and to see which of your pet lines tend to score well. The common mistake is following the most popular move without understanding it, which leaves you lost as soon as the opponent deviates. Another mistake is trusting win rates from a small number of games. A good habit is to use the explorer to build your repertoire, then check each line with a few model games to learn the typical plans. Memorize ideas first, and treat move lists as secondary.
Compare it with Novelty. A novelty is a move that has not been played before in a known position of an opening, introduced to take the opponent out of their preparation and into unexplored territory.
Also worth reading is Opening book. An opening book is a database of opening moves and positions that an engine or program consults to play known theory quickly, instead of calculating each early move from scratch.
Also worth reading is Out of book. A player is out of book when the game reaches a position that neither side is recalling from opening knowledge or preparation, so from that move on the choices have to be worked out at the board.
Computer terms such as "Opening explorer" are most useful next to a coach who reads your games with you, which is how a first lesson with George Li works.
Related terms
Opening theory is the body of knowledge about the opening, made up of the known moves, plans and evaluations of the main lines that players have tested over many games.
An opening repertoire is the personal menu of opening lines a player has decided to rely on, so that with either color they know where they are heading and have answers ready for the opponent's most likely choices.
An opening book is a database of opening moves and positions that an engine or program consults to play known theory quickly, instead of calculating each early move from scratch.
A chess database is a searchable collection of games, stored in a standard format, that lets a player look up positions, study opponents, and see how often moves have been played and what results they scored.
A novelty is a move that has not been played before in a known position of an opening, introduced to take the opponent out of their preparation and into unexplored territory.
A player is out of book when the game reaches a position that neither side is recalling from opening knowledge or preparation, so from that move on the choices have to be worked out at the board.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
How much does chess coaching cost?
Published rates for private, group and subscription chess coaching, with the source and the date of each.
A game review, a read on your level and a written study plan from George Li.
Want to spot this in your own games?
A first lesson starts with your games: George reviews them and builds a study plan around what he finds.