In duplicate bridge, a board is an item of equipment that holds one deal, or one deck of 52 cards distributed in four hands of 13 cards each. The design permits the entire deal of four hands to be passed, carried or stacked securely with the cards hidden from view in four pockets. This is required for duplicate bridge tournaments, where the same deal is played several times and so the composition of each hand must be preserved during and after each play of each deal. Each board is usually marked with the following information: board number – (from '1' to as high as '36') identifies the deal and helps to order the play of multiple deals; compass directions – used to match the four hands to the four players at a table; dealer – designates which player is the "dealer"; this designates the player who is to make the first call of the auction; vulnerability – often represented by color code: a "vulnerable" partnership is usually shown in red and a "not vulnerable" partnership in green, white or no color. Most designs include a slot or pocket to hold a paper travelling score sheet. Colloquially, the term board may refer to one deal plus its and . When bridge is played online, there are no physical boards, nor physical cards, but the software emulates all of the features of duplicate boards and the unit of the game is commonly called a board. History First used in duplicate whist in the 1890s, the devices were called duplicate whist trays. Since the first in November 1891, numerous patents have been registered incorporating a variety of shapes, sizes and materials and having various means of inserting and retaining the cards in place in the trays or apparatus, as they were often referred to in the patent description. Amongst the earliest versions were those manufactured by Ihling Brothers & Everard of Kalamazoo, Michigan, and referred to as the Kalamazoo Tray, a square tray, getting award-winning recognition at the 1893 Chicago World Fair. The company's interests in duplicate whist trays were purchased by The Duplicate Whist Co. in 1899, which introduced a tray known as the Paine's Duplicate Whist Tray after its president, Cassius M. Paine; Paine used the U.S. Playing Card Co. of Cincinnati as his sole manufacturing and sales agent. Originally, trays were sold in sets of 8, 12, 16 and 20;