Analysing a match

#Running an analysis

When a match ends, press Analyze in the match list, or use the analysis controls on the board. The engine replays every decision of the match, works out what the best play was, and records what each actual play cost against it.

#On this device or on our servers

The run modal asks that first, because the answer decides everything below it.

On this device uses the same WebAssembly engine you play against. It is free, needs no account, and the match never leaves the browser. It is bounded by what the device can do: a whole-match pass runs up to 3-ply here, and rollouts are not available at all, the browser engine having no rollout path.

On our servers runs the same analysis on our hardware, against models we do not publish for download, at depths a browser cannot reach. It needs an account, and how much of it you get is what a plan changes. See Accounts and plans.

#How deep

3-ply is the one to reach for. Below it the numbers move under you; above it the cost grows much faster than the accuracy does, which is why the deeper rungs are better spent on a handful of positions than on two hundred of them.

Whole-match passes default to 2-ply and a single position to 3-ply, both adjustable in Settings and from the strength menu on the analysis itself.

#Analysing part of a match

A run does not have to cover everything. Beside the whole match you can re-run only the moves already flagged as errors, everything from the move you are looking at onwards, or the decisions that were close enough for the depth to matter. Re-running a narrow scope deeper is usually a better use of a rollout than deepening the whole match.

#Studying your mistakes

Once a match is analysed, its mistakes can be turned into a study: you choose which ones, and each comes with the play you made and the play the analysis preferred. See A study from a match.

#Importing a match

Press Import Match and load one of:

The last three carry that program's own analysis, so an imported match opens with its evaluations already attached and you can compare them against ours before running anything.

A .mat import is kept in this browser until you choose to save it to your account. Where your matches are kept explains why, and how to save one.

#Where your matches are kept

Without an account, every match lives in this browser only. Clearing site data, or playing in a private window, removes it, so export anything you want to keep.

Signed in, a match can also be saved on our servers, where no browser setting can remove it and any device you sign in on can open it. In Matches, the cloud icon on each row says which it is: a cloud with a tick is saved on the server, and a cloud with an arrow is in this browser only. Press the arrow to save that match.

Some matches are saved for you and some wait for you to choose:

A .mat import is left to you on purpose. A free account holds a limited number of saved matches, and loading a folder of old .mat files should not fill those slots without asking. That is also why a transcription can bring up a saving prompt that an import does not: see the next section. A match that could not reach the server because you were offline is saved as soon as the connection comes back.

#When your saved matches are full

A free account shows how many saved matches it is using at the top of Matches, and the plans page lists how many it holds. Saving one more once they are full opens a prompt that names your oldest saved match:

• Free up a slot & save moves that oldest match to Deleted matches and saves the new one in its place
• Not now leaves the new match in this browser only, where you can save it later from its cloud icon

Nothing is destroyed. A match moved out this way keeps its analysis, can be put back from Deleted matches at any time, and returns by itself if you upgrade. While it is out, its share link stops working. Ordering a server analysis needs a copy of the match on the server, so it can bring up the same prompt. Standard and Pro hold unlimited saved matches.

#Tagging your matches Standard

Every saved match carries a line of tags under its players in Matches.

The first chip is automatic: where the match was played (against HedgeHog, online or over the board) or the site it came from, read from the match itself. A chip drawn with a dashed outline is a guess, for example a transcription assumed to be over the board. A match nothing could place shows Where?: press it and say where it was played. You can hide the automatic chips in Settings, under Match tags; they still work in the filter.

The coloured chips are your own tags, and only you see them. Press + Tag, type, and press Enter to add a tag you already have or to create a new one. Names are matched without regard to capitals or spacing, so "Tired" and "tired " are the same tag. Backspace in an empty box removes the match's last tag, and Escape closes the box. A tag name is 1 to 32 characters, one match carries up to 20 tags, and an account keeps up to 100. A tag name cannot start with auto:, which names the automatic chips.

To tag many matches at once, press Select, tick the rows (up to 100), or select every match that fits the current filter (up to 5,000), then Add or remove tags. Each tag shows whether all, some or none of the selection carry it; change the ones you want and press Apply. A match that already has 20 tags is left out, and the message says how many were.

You can also tag a match as you import it, under Extra tags, and at the end of a match against HedgeHog from the final card. A tag given to a match that has not reached the server yet goes up with it.

Settings, under Match tags, renames, recolours, merges and deletes tags. Renaming a tag to a name another tag already has merges the two. Deleting a tag says how many matches it comes off, and Undo on the message brings it back.

#Filtering by tag

The Tags button on Matches filters the list by the automatic facts (where it was played, the opponent, broadcast, the site, the event) and by your own tags:

• Choices in one section are alternatives: Online or Over the board.
• Sections combine: Online and tagged Club night.
• Not excludes a value. An exclusion never hides a match whose fact was not detected, so "not against HedgeHog" keeps an old import nobody placed.
• Your own tags have an Any or All switch: a match with any of the chosen tags, or only those with every one.

The filter is part of the page address, so a bookmark or a reload keeps it. Matches still only on this device have no tags yet, and are listed apart while a tag filter is on.

#Tags on the Stats page

Stats has the same Tags button, and every card says how many analysed matches it rests on (n = 14). A card resting on only a few says so in its headline. The percentile ranking always compares all your matches, whatever the filter.

You can keep a filter as My default filter, and Stats opens with it on every device you sign in from. A strip above the numbers always says that it is on and how many analysed matches it shows out of all of them. From the strip, Show all sets it aside for this visit, Edit changes it, and Stop using a default removes it. A change turns the strip amber, with Save to make the change your default and Revert to go back to it. A filter in the page address, such as a bookmark, is used instead of the default. If the default names a tag you have since deleted, the strip says so. The first time you open Stats with matches against an engine, you are asked whether to leave them out; the answer is remembered, and Stats never sets a default you did not choose.

Matches never opens with the default, so a match you just played is always in the list, but it offers Apply my default here to filter the list the same way.

Your XR by source compares your XR across where you played, the opponent, the site, or your own tags, within the current filter, with the number of matches in each row. Press a row to filter Stats to it. A match can carry several tags, so by tag the rows do not add up to the total.

#Exporting a match

Export Match in the sidebar downloads the current or completed match as a .mat file, which GNU Backgammon, eXtreme Gammon and other backgammon software read. A .mat file holds the moves only, so a program that reads it finds no analysis in it.

To keep the analysis, use Export match to .ogxm (with analysis) in the menu of the analysis page. The OGXM format stores the moves and the analysis together, which is what a flashcard tool such as AnkiGammon needs to find your mistakes. Right-clicking the export button in the match list downloads the same file, carrying the analysis when the match has one.