Players

Three to five may play, but there are only ever three active players at one time. With four players, the dealer sits out; with five, cards are dealt to the two players on the left of the dealer and the one on the left. Deal and play are clockwise.

Cards

Frog is played with a pack of 36 cards, the 2s, 3s, 4s and 5s being removed from a standard 52-card French-suited pack. The cards rank and score, as in most ace–ten games, as follows:

Deal and auction

The first dealer is chosen by any desired method. The dealer deals a packet of 3 cards to each player, beginning with eldest hand to the left, then 3 face down on the table as the widow (or blind in British rules), and finally two rounds of 4 cards each, i.e. 3-(3)-4-4, so that each player has a hand of 11 cards.

Beginning with eldest, players may pass or bid for one of the following games:

Frog
Name of contract	Exchange with scat	Suits	Chips/point
Frog	Yes	♥ only	x 1
Chico	No	♣, ♠ or ♦	x 2
Grand	No	♥ only	x 4

There is one round of bidding, but a player who announced "Frog" and is outbid by "Chico" may immediately raise to "Grand"; otherwise must pass. The winner of the auction is called the "bidder"^{[lower-alpha 2]} and plays alone against the other two active players. The bidder may not play a higher contract than that which won the auction. In a Frog the bidder exposes the widow, picks it up and discards 3 cards, placing them face down to one side. In Chico and Grand, the widow is untouched.

Play

Eldest leads to the first trick. Players must follow suit if able; if unable to follow, they must trump if possible. There is no requirement to head the trick. The trick winner takes up the trick and lays it face down before leading to the next trick.

Scoring

Once the eleventh trick is played out, players count up their card points. For this purpose the widow belongs to the bidder. There are 120 points in the pack and the bidder must score at least 60 to win.^{[lower-alpha 3]} In Frog, he scores 1 chip for every point above 60 from each active player. Chico scores double, and Grand quadruple (see table above). If the bidder loses he pays the same rate to every player at the table. This means that if four or five play, the non-active players are also paid by a bidder who loses, but are not required to pay if the bidder wins.

Solo or Slough

The 1922 Official Rules published a variant of Frog called Solo or Slough. There were changes to some of the contract names and values:^[4]

Solo or Slough
Name of contract	Exchange with scat	Suits	Chips/point
Frog	Yes	♥ only	x 1
Simple Solo	No	♣, ♠ or ♦	x 2
Heart Solo	No	♥ only	x 3

Other differences were:

• The number of possible players increased to seven
• The cards were fanned face down; the player with the lowest chose whether to be dealer or eldest hand for the first deal
• Cards were dealt singly, the 1st, 4th and 8th going to the widow which was called the slough
• In a Frog, the slough was not exposed
• Players started with 11 chips of one colour each worth 10, and 10 chips of another colour, each worth 1
• The first player unable to pay for winnings lost the game
• There were three systems for payments to or from non-active players:
  • They only received payments
  • They paid and received
  • They paid and received for a Solo, but only received for Frog
• In a variation called Penalty Frog, the bidder paid the Heart Solo rate if a Frog contract was lost

Straight Solo

The same rules mentioned a Straight Solo in which the only change to the Solo/Slough rules above was that the Frog contract was omitted. In a Simple Solo contract, 1 chip was paid per point and 2 chips in a Heart Solo.^[4]

Coeur d'Alene Solo

The same rules introduced a variant called Coeur d'Alene Solo or simply Coeur d'Alene, this being the name of a town in Idaho. This was the same as Solo or Slough except that there were fixed payments for winning instead of point-based payments. Payments were in the ratio 1:2:3 e.g. 25¢ for Frog, 50¢ for Simple Solo and 75¢ for Heart Solo.^[4]

Coeur d'Alene
Name of contract	Exchange with scat	Suits	Payment
Frog	Yes	♥ only	25¢
Simple Solo	No	♣, ♠ or ♦	50¢
Heart Solo	No	♥ only	75¢