Saat-Aath (7-8)
Introduction
Saat-Aath (which is Hindi for 7-8) is an Indian trick-taking game for two players. It is essentially a two-player version of the three-player game 3-2-5. Each player aims to win as many of the 15 tricks (known in India as 'hands') as possible: the dealer has a target of 7 and the non-dealer (who chooses the trump suit) has a target of 8.
Players and Cards
There are two players.
A 30-card pack is used, which is made from a standard 52-card pack by removing all the 2's, 3's, 4's, 5's and 6's and also the 7's of clubs and diamonds.
In each deal one suit is chosen as the trump suit. Irrespective of which suit is trumps, the top trump is always the 
7 and the second highest trump is the 
7. These are followed by the cards of the chosen suit in descending order: A, K, Q, J, 10, 9, 8.
In the other three suits the ranking of cards from high to low is A, K, Q, J, 10, 9, 8.
Deal
The first dealer can be chosen by any convenient method, for example by drawing cards from the shuffled deck. Thereafter, if a series of games is played, the players take turns to deal.
The dealer shuffles, offers the cards to the non-dealer to cut, and deals a hand of five cards to each player. The players pick up and look at their cards and the non-dealer chooses and announces (calls) the trump suit.
The dealer then deals a row of five cards face down in front of each player, and then a card face up on top of each of the face down cards. Each player now has 15 cards: a hand of five cards and five stacks consisting of a face up card on top of a face down card.
Play
The cards are played in a series of 15 tricks ('hands') each consisting of two cards, one from each player. If the two cards of a trick are the same suit the higher card wins. If they are different suits and one of them is a trump then the trump wins. If they are different suits and neither is a trump then the first played card wins (irrespective of which is higher).
The non-dealer (also known as the cutter or caller) leads to the first trick (i.e. plays the first card of the first 'hand'). The winner of each trick (hand) takes the two cards, stores them face down, and leads to the next trick (plays another card to begin the next hand). The cards that are available to play are the cards in a player's hand and the player's face-up cards on the table. When a face-up card is played from the table, the face down card that was under it is turned face-up and becomes available to play in a future trick.
The first card of a trick can be any of the player's available cards. The other player must respond if possible by playing a card of the same suit. If the second player has no card of the suit led by the first player, neither in hand not face up on the table, they may play any of their available cards.
Note that throughout the play the top trumps (Sevens) are treated as belonging to the trump suit and not to the suits printed on them. Suppose for example that clubs are trump. If the first player leads a club, the other player may play either a club or a Seven, and must play one of these if available. Only if the second player has no clubs and no Sevens can a non-trump card be played. If the first player leads for example the A, the second player must if possible play a spade but not the Seven (which is a trump). If the second player has no spades (except possibly the Seven) they may play any card - they could win by playing any club or Seven (winning with a trump in this way is known as 'cutting') or they could throw some unwanted non-trump card and allow the first player to win the trick.
A player who leads a face-up card from the table that has a face-down card under it is allowed to wait until both players have played to the trick before turning over the face-down card
The play continues until all 15 tricks have been played and both players have run out of cards.
Winning
If the dealer wins more than 7 of the 15 tricks (hands) the dealer wins the game.
The non-dealer/cutter/caller needs more than 8 tricks (hands to win the game.
If the dealer wins exactly 7 tricks and the non-dealer exactly 8 the game is a tie with no winner.
Variations
Some play that the Sevens of hearts and spades have no special status: they are simply the lowest cards of their respective suits.
Some play that (as in 3-2-5) the winner has an advantage in the next game. After the first 5 cards each have been dealt, the loser must hold out their cards face down and the winner draws a card from it. The winner then gives back an unwanted card in exchange. The winner is not allowed to give back the card just received - it must be one of the other five cards.
If the winner won by a margin of more than one trick, this process is repeated until the winner has drawn a card for each trick by which they exceeded their quota. For example if the dealer wins by taking 10 tricks, 3 more than 7, then in the next deal this player, who is now the non-dealer, will draw three cards from the loser. Before each draw the loser is allowed to look at and rearrange their five cards before offering them to the winner, and to try to mislead the winner as to where the best cards are located.
Other Websites
Other descriptions of 7-8 in English can be found at
By Googling 'Saat-Aath card game' or a similar phrase, several video introductions can be found with commentaries in Hindi.