Rare Moves

Available in: Builder

Rare Moves analyzes your existing repertoire to identify moves that are highly unlikely to be played in real games. Using probabilistic models from Maia or Lc0, the system evaluates each move in your repertoire against expected human play, highlighting low-likelihood continuations that rarely occur in practice. This allows you to review and curate speculative or obscure lines while keeping your repertoire focused on moves that are realistically expected over the board.

Clicking Run Analysis processes your repertoire using the selected engine and settings. Once complete, the results are displayed in a paginated table for easy review and action.

This feature helps you:

• + Identify low-probability moves in your repertoire that are unlikely to be played in real games
• + Review speculative or obscure branches without altering your repertoire structure
• + Focus your preparation on moves that align with realistic human expectations
• + Improve clarity and confidence in your opening preparation

Rare Moves

Once the analysis has been run, the results are presented in a paginated table showing all detected rare moves that meet the configured criteria.

For each identified rare move, this section displays:

• ◦ Rare Move: A move currently present in your repertoire that has a very low likelihood of being played according to the selected probabilistic model.
• ◦ Likelihood: The predicted probability of the move being played. When using Maia, this reflects expected human play at the selected rating. When using Lc0, this represents the model’s assessment of how rarely the move occurs.
• ◦ Ply: The ply number at which the rare move occurs within your repertoire tree.
• ◦ Actions: Provides quick controls to Go To the position or Remove the entry from the results list, allowing you to acknowledge the rare move without modifying your repertoire.

At the top of the table, the total number of detected rare moves is shown along with the active likelihood threshold, which dynamically filters the list to include only moves at or below the configured probability.

Note: Removing a rare move clears it from the current analysis results only. It does not delete or alter the move in your repertoire. You can rerun the Rare Moves analysis at any time to regenerate the list based on your current settings.

Rare Moves Settings

The Rare Moves analysis can be configured using the following options:

• ◦ Engine: Choose between Maia or Lc0. When Maia is selected, you can specify a target rating level between 1100 and 1900 to match expected human play.
• ◦ Maximum Likelihood Threshold: Defines the upper probability limit for a move to be considered rare. Moves exceeding this threshold are excluded from the results.
• ◦ Ply Range: Controls which portions of the repertoire tree are scanned by defining the minimum and maximum ply to analyze.
• ◦ Find Rare Moves For: Limits the analysis to moves for White, Black, or Both, based on how your repertoire is structured.

Note: Maia and Lc0 identify rare moves based on the probability of moves being played rather than strict engine optimality. Because these models are trained on millions of games, their predictions reflect realistic human expectations and practical play patterns rather than theoretical perfection.