1 deck. Easy. Unlimited redeals.
Short Solitaire uses 52 cards. You have 6 vertical tableau piles with 4 cards in each pile. The next (25th) card is placed above the tableaus. It will be the starter card of the foundation. The remaining three cards of the same rank will be placed next to it during play as soon as they become available.
You can move cards from one tableau pile to another and from the stock pile to a tableau pile. Build tableau piles down regardless of suit. Kings can be placed on Aces. Only one card at a time can be moved. When one of the tableaus is empty it may be filled only with a card whose value is one less than the starter card.
When you have made all the moves initially available, begin turning over cards from stock. 3 cards at a time are turned over. Move cards from stock to the tableau piles and to the foundations following the rule above. You can turn over the stock pile as many times as you wish.