Meet the 40-card deck
Use four suits—♠ spades, ♥ hearts, ♦ diamonds and ♣ clubs—with ranks Ace, 2, 3, 4, 5, 6, 7, 8, 9 and 10. For sums, an Ace counts as one. Kings, Queens and Jacks are not used.
You play one card from your own hand on an ordinary turn. A legal action may allow additional groups to be handled before the turn finishes.
Loose cards and captures
A loose card lies unclaimed on the shared table. A played card can capture matching loose cards, a build of its value, or table groups that add up to its value. Several separately complete groups can be taken in one legal capture sequence.
You cannot discard a second independent loose card of a value already present as a loose card or build. Use a legal capture or other permitted action instead.
Building means keeping the match
Combine the card you play with loose table cards to make a build of value 1–10, while retaining a card of that value in your hand. For instance, hand 5 + loose 4 makes Build 9 only if you keep a 9. An additional completed group placed on that build must itself total nine.
Your matching card is a commitment to that build; dropping your last matching card onto your build is not allowed. A matching-rank pair can also establish a compound build of that same value: hand Ace + loose Ace makes Build Ace if you retain another Ace. The two cards are separate complete groups, so the opponent cannot change its value as if it were a simple two-card sum build. Similarly, hand 5 + loose 5 may declare Build 5 when another 5 is retained, or Build 10 when a 10 is retained.
Ownership and changing a build
A player may change an opponent's simple two-card, single-group build by adding a card to increase its value and retaining the new matching capture card. Example: opponent's 4 + 5 = Build 9, then your Ace makes Build 10 if you retain a 10. You cannot raise your own build this way or change a compound build.
Exposed captured cards
Only the top card of an opponent's captured pile is accessible; covered cards are hidden. A pile's exposed card cannot by itself be used to start a brand-new build. It can help complete a group on an established build or a table-grounded capture.
Newly exposed cards may be used in sequence if each preceding group was completed legally. You cannot take two covered cards at once to finish one group.
What stays visible
The capturing hand card must remain exposed on top of the capturing player's pile. On a build, higher-ranked cards sit underneath lower-ranked cards within each group, and newer completed groups sit above older ones. In competitive modes, buried build cards are not revealed simply by inspecting a stack.