Create a Position

Create a Position (under Improve in the navigation) opens BackgammonDB's board editor: the one place you can change a board. Build a position from scratch or bring one in from anywhere — a match you're reviewing, a saved position, a share link, an XGID string — then move checkers freely, set the dice and cube, and watch the engine analyze as you edit. There is no analyze button and nothing to submit: the answer follows every change.

You don't need a notebook to use it. The editor on its own is a scratchpad — the lab — and a position lives there only as long as you keep it on the board. To keep one, save it to a notebook.

Ways in

• The navigation — Improve ▸ Create a Position opens the editor on the starting position.
• The dashboard — the Position editor → tile does the same.
• Match review — the pencil chip under the candidate list, Open this position in the analyzer, carries the current decision over with its match context and its analysis. See Engine analysis.
• A shared position — the same chip on the /share screen.
• Saved positions — Analyze → on any match position on the Saved page; Open in notebook → on a notebook entry opens it inside its notebook instead.
• Set the Board — the menu in the editor's header: the Starting position (the standard opening setup), an Empty board (all thirty checkers in the side trays, to place yourself), or Paste an XGID or a share link. The XGID= prefix is optional — a bare -b----E-C---eE---c-e----B-:0:0:1:52:0:0:0:9:10 works too.
• A link — /analyze?xgid=… opens the editor on that position directly.

The screen

The header holds Set the Board, the score line (click it for the match settings), Undo and Redo, Settings, Keyboard shortcuts, and ×, which closes the editor. On a phone the header buttons fold into a ⋮ menu. Under the board sits the analysis region: the engine bar, the candidate list, and the two comparison cards, with the action row along the bottom.

Editing checkers

Everything obeys one rule: checkers are conserved. Each side always has exactly fifteen — the side trays act as each player's reserve — so the board can never enter an impossible state. Landing on a point the opponent holds sends all their checkers there to the bar, where the rules of the game put them; the trays are the reserve you build a position from, and a hit never adds to them.

• Stamp tool — click a side tray to load that color (a mini-checker follows your cursor). Each click on a point or the bar drops one checker. Click the tray again — or press Esc — to unload.
• Drag — drag any checker to another point, the bar, or a tray. While you drag, a ghost preview shows exactly where the checker will land — including any opponent checkers a hit would send to the bar — and releasing commits exactly what the preview shows.
• Marquee — drag on empty board space to rubber-band a selection (partially covering a stack selects its top checkers). Shift-drag adds to the selection; clicking the base of a point — or an occupied half of the bar — selects that whole stack, including any checkers hidden behind a count badge. Dragging any selected checker moves the whole group, keeping its visual shape — at the board edges the shape pins in place rather than spilling off. The bar is the exception: it has no column to arrange a shape around, so a selected bar stack travels on its own and lands as one stack wherever you drop it. With a selection made, B sends it to the bar and Del sends it to the tray.
• Remove — right-click a checker to send it back to its tray. On a phone, load a tray and use the Add / Remove toggle that appears over the board: in Remove mode each tap removes one checker instead of placing one.
• Undo / redo — every gesture is one undo step. Ctrl+Z / Ctrl+Shift+Z, or the header buttons. A popover counts as a single gesture: drag the match-length slider across five values, or set one die and then the other, and closing it leaves one step to undo — not five.

Phones support the stamp tool and the Add / Remove toggle; drag and marquee are pointer-precision features and stay on the desktop.

Dice, cube, and match context

The board always shows the question on the side of the player being asked it — dice for a checker play, a doubling cube for a cube decision. Clicking a side is the one gesture that drives all of it.

• Who's on roll — click either half of the board. That player takes the decision (the header's highlight moves to their name), and the popover for it opens on their side. Clicking the side that already has it just opens the popover; the other side's slot is outlined so you can always see where to click.
• Dice — the popover picks the Decision type (below) and both faces from a grid of the twenty-one rolls. Switch active player at the bottom hands the same question to the other side.
• Cube — during a checker decision the cube sits on the bar; click it to make it Centered or give it to a side (Bottom owns / Top owns) at 2, 4, 8… A centered cube shows 64, the largest face of the doubling die, meaning "available" rather than "worth 64" — which is why 1 is never an option and an owned cube always starts at 2. The values on offer stop where the match score does (see The cube can't go out of range below).
• Match — click the scoreboard region (over the bear-off tray), or the score line in the header, to set the Match length (0 = money), both scores, Crawford (Crawford game or Post-Crawford, available when a player is 1-away), and the Jacoby rule (money play only). The analysis is score-sensitive, so this matters for cube decisions especially. Each saved position freezes its own match context — change the score and save again, and both versions sit side by side in the notebook.

Decision type

Dice on the board always mean a checker play. Without dice there are two different cube questions, and the popover picks between them:

• Double — should the player on roll double? The candidates are No double, Double / Take, Double / Pass.
• Take/pass — the double has already been offered; the candidates are just Take and Pass.

Either way the cube leaves the bar for the decider's own side, marked with a ? and showing the value being offered — the turned cube, not the one sitting on the board. So the popover asks for one number, Cube offered, and the cube underneath follows from it: an offer of 2 can only have come from a centered cube, and anything higher from one the doubler already owned at half the offer.

The cube can't go out of range

The board never shows a double nobody could make, so an edit that puts the cube out of range shortens it rather than leaving it wrong:

• The match caps it. The cube stops being worth turning once it covers what the player furthest from victory still needs. Drop a 25-point match with a 32-cube down to 9 points and the cube becomes a 16 — that's all a 9-pointer is worth. The same applies as the score moves.
• The cap applies to the offer. In a 9-point match a player may legally be holding a 16-cube for a checker play, but turning it would offer 32, which the match can't pay. Switching that board to a double leaves an 8-cube offering 16.
• Crawford has no cube at all. In the Crawford game the cube is dead: it sits centered, nobody can own it, and Double and Take/pass are unavailable — the board can only ask a checker question. Clearing Crawford brings the cube back.
• Ownership follows the doubler. Editing the board so the new decision-maker couldn't legally be holding the cube re-centers it, since you can't double a cube your opponent owns.
• A centered cube is always 64. On the bar a centered cube means "undoubled and available", so it can only read 64 — going back to a checker play from an offered 2 resets it rather than parking an impossible 2 in the middle. A cube somebody owns survives the switch untouched: holding a 4 for a checker play is a perfectly good position.

Each of these is folded into the edit that caused it, so one Ctrl+Z puts both the setting and the cube back.

Bringing a take/drop decision over from a match review therefore shows you the take, not the double — the offer is assumed to have happened, which is the question that was actually being asked.

Switching decision type never moves the roll. The player whose side you are looking at is the one being asked, in every moment: on an offer they are deciding whether to double, on a take/pass they are answering a double from the other side. What changes hands is who made the offer, not who is facing it — so the board doesn't jump to the other player under you. The cube doubles or halves to match, and the whole switch is a single undo step.

Analysis

Analysis is ambient: the moment a position settles — both sides have checkers, someone is on roll, and the dice or the cube question is set — the editor quietly evaluates it. While the new answer is on its way the candidate list is replaced by a placeholder in its own layout, so nothing moves; the result then replaces it in place. Until the position is complete, the analysis region says what is missing ("Set who is on roll to analyze this position").

The engine bar above the candidate list is the same one match review uses — see Engine analysis for the badge table and the honest plies:

• ◔ Quick is the ambient default, fast enough to keep up with your editing. Smart is one click away, and the badge follows whatever you clicked last. Deep is shown disabled; its tooltip says it is coming with accounts.
• ⚡ Book — early-game positions covered by the precomputed opening book come back instantly at full depth. There is no other depth to reach, so the tier chips disappear.
• 📄 XG or 📄 GNU — a position brought in from an analyzed match arrives with that file's own analysis already on screen, badged with the engine that produced it and the depth it recorded (XGR+, 3-ply, a rollout…). Nothing is guessed about how it compares to our depths: it gets its own chip beside Quick and Smart, so you can try our engine against it and flip back whenever you like.

Two positions cannot be evaluated, and the region says so instead of guessing: a board with no legal moves (an empty board mid-setup lands here) shows No legal moves in this position, and a server that cannot be reached shows Analysis unavailable with a Retry chip.

Hover any tier chip for its honest engine depth.

Saving a position

Ambient analysis is ephemeral — editing on simply moves to the next position. To keep one, click Save to notebook ▾ in the action row (or press S). The picker lists your notebooks; pick one, or choose New notebook… to create one for it. The entry stores the board, the score and match length, the cube, who is on roll, and the analysis on screen at its best-known depth. Editing on afterwards leaves the entry as it was; the board in front of you is a new position again.

The chip is disabled until someone is on roll — there is nothing to save before then. Once a position is saved the editor switches into that notebook, with the entry on the board; Notebooks describes what changes there.

Sharing

Share this position sits beside the save chip — the same sheet as sharing from a review. Whatever analysis is on screen goes into the link, so the recipient sees the candidate list you were looking at; choose the plain XGID format instead to send the position alone. The chip appears in the lab only.

Undo and redo

Ctrl+Z and Ctrl+Shift+Z (or the header arrows) step through every editing gesture — checker moves, dice, cube, match settings, decision type — one gesture per step. The history belongs to the board on screen: opening a different position starts it fresh.

Keyboard shortcuts

Press ? for the overlay. It lists only the keys this screen honors — a shorter set than match review, because the editor has no action cursor to move and no played move to compare against.

Key	Does
1–9	Select a candidate by rank
B	Select the Best candidate — or, with checkers selected, move them to the bar
]	Toggle the candidates strip
I / A / R	Show the position before the move · the move arrows · the resulting position
D	Cycle those three
O	Toggle the best-move Overlay
F	Flip which side bears off
Ctrl+Z / Ctrl+Shift+Z	Undo / redo the last editing gesture
Del	Send the selected checkers to the tray
Esc	Unload the tray color, then clear the selection
S	Save this position (in the lab, opens the notebook picker; in a notebook, stars the entry)
N	Notes & tags for this entry (in a notebook)
L	Share this position (Link)
← / →	Previous / next entry (with a notebook open)

B means two things, exactly as the overlay lists it: with nothing selected it picks the best candidate; with checkers selected it moves them to the bar.

Result view pauses editing. R draws the board after the selected candidate's move, which is not the position on the board — so the checker-editing layer stands down until you press I or A to come back. The same three-way toggle sits under the candidate list if you'd rather click it.

The ] key (or the corner button) collapses the analysis region to a single bar and expands it again, as in match review. The choice persists between sessions.