red tag; red label
Typically a red tag attached to sold or discounted goods in shops; also used for red labels more generally.
Bargain items have red tags on them.
All items with red tags are half price.
In traditional Japanese gambling decks, the suit corresponding to swords; a domain-specific term.
In hanafuda, 赤札 can refer to the sword cards.
Compound of 赤 (red) and 札 (tag, card). The card-game sense comes from the red-colored sword suit cards in traditional decks.