Analysis board guide: what every control does

An analysis board is a chessboard with an engine attached and a set of controls around it. Learn what each control does and you can use any of them, from the free Lichess board to desktop software. ChessHelper (chesshelper.ai) puts the same core pieces, an evaluation bar, arrows and alternative lines, on top of your Chess.com and Lichess games, with engine strength you can lower to your level. Below, each control is explained with the Lichess board as the reference, because its settings are public and its code is open source.

The evaluation bar and the number above it

The bar shows who is better and by how much. The number is in pawns from White's point of view: +1.00 means White is better by roughly a pawn's worth, −0.50 means Black is slightly better. An "M" value such as M3 means the engine has found a forced mate in three moves.

Two cautions. First, the number is an estimate at a given search depth and it moves as the engine thinks longer, as the table further down shows. Second, the same evaluation means different things at different levels. +1.50 in a quiet endgame is often a win for a strong player and very playable for a club player. Read the bar as a direction, then read the lines to see why.

Multiple lines (MultiPV)

By default an engine shows its single best line. Multiple lines asks it to show the top two, three or more moves with an evaluation for each. On Lichess the setting is a slider labeled "Multiple lines" in the engine settings, from 0 to 5. Setting it to 0 turns the engine lines off.

Multiple lines are the most useful control for learning, because they tell you whether a move is the only good one or one of several. If the top three moves are all within 0.2 of each other, your choice was a matter of taste. If the best is at −0.4 and the next is at +2.0, the position had one right answer.

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In the position above, Stockfish at depth 20 with four lines gives:

Three different defenses of f7 all leave Black fine. The lesson for a beginner is that the threat matters more than the exact choice. The natural developing move 3...Nf6, which fails to defend f7, allows 4.Qxf7#.

Depth and search time

Depth is how many moves ahead, in half-moves, the engine searches along its main lines. More depth means a more reliable evaluation and a longer wait. Lichess does not expose a depth number as the setting; it gives you a search-time slider from 1 second up to 30 seconds, and on desktop also 60, 120, 300 seconds or unlimited. The depth reached is shown next to the evaluation.

The same position at three depths shows why this matters:

At low depth the engine thinks Black is clearly better; at depth 22 the edge has shrunk to about a third of a pawn and the best move has changed. For finished-game review, let the engine settle until the top move stops changing, especially in sharp positions.

Threads and memory

Threads set how many processor cores the engine uses; memory sets the size of its hash table, where it stores positions it has already searched. More of both lets the engine reach a given depth faster. On a laptop running on battery, fewer threads keeps the machine cool at the cost of speed. Lichess shows a recommended thread count and lets you change it.

Arrows

Engine arrows draw the best move, and with multiple lines turned on, the alternatives, directly on the board. They save you reading notation. The risk is that you follow the arrow and skip thinking. A good habit is to guess the move before you look at the arrow. You can also draw your own arrows and circles on most boards to mark plans while you annotate.

Opening explorer

The opening explorer shows which moves have been played from the current position and how they scored. Lichess offers three databases: a Masters database of over-the-board games between strong players, the much larger database of games played on Lichess, and a Player tab that shows the games of any single Lichess user. The last is useful for checking your own repertoire: it shows where you deviate from your usual moves.

The explorer answers a different question from the engine. The engine says what is best; the explorer says what people actually play and how it goes for them. Use both when you find the point where your game left known theory.

Endgame tablebases

A tablebase is a precomputed database of every position with a small number of pieces, and it gives the exact result with perfect play: win, draw or loss, with the distance to mate or to the next capture. When few pieces remain, the Lichess explorer switches to a tablebase view. Lichess's tablebase server uses Syzygy tables, complete for seven pieces, plus a partial eight-piece set.

Where a tablebase applies, it outranks the engine evaluation. An engine might show +5.00 in a rook endgame that the tablebase proves is a draw. If you are reviewing an endgame you lost, check the tablebase first to see exactly where the result changed.

Which board to use

For free full-strength analysis, the Lichess board covers every control above. If you want the same feedback pitched at your level, with your games stored and charted for you, ChessHelper is our pick. Desktop programs add database search and opening preparation; the trade-offs are in our desktop vs browser vs mobile guide, and the review routine that uses these controls is in how to analyze your chess games.