Mahjongg Solitaire is a solitaire matching game that uses a set of Mahjong tiles. The 144 tiles are arranged in special layouts with their faces upward. The object of the game is to clear the playing area of tiles by matching pairs of tiles. Players can only match pairs of tiles where each tile has at least one side (left or right) free and no other tiles placed on top. Matching tile pairs can be removed by clicking on each tile in the pair.  

The goal of the game is to clear the layout by pairing up all the tiles. Solving a Mahjong Solitaire board puzzle is all about avoiding a situation where there are no available matches left. There is always at least one valid solution for the board.
 A player can only remove the tiles one pair at a time. There are a total of 72 pairs in a game of Mahjongg Solitaire. Like cards, the tiles have standard suits. These suits are Wans, Circles, Bamboos, Winds, Dragons, Flowers, and Seasons. You can also find this image of them in the game menu.

Exposed pairs of identical tiles are removed from the layout one at a time, gradually exposing lower layers to play.  
When matching pairs, Seasons and Flowers are the only suits you do not need to match exactly. Any Season or Flower combination counts as a pair because there is only one of each tile.

There are few tips that can help you solve a puzzle and avoid ending up in an unsolvable situation:

1. The general strategy is to keep removing matching tiles so that each removal opens up more possibilities for future tile matching. If you have a pair that does not open anything, leave it until you need it. As you can see in the example below, removing the top tile opened 5 more matches. That is extremely useful!

2. Don't forget that you should open up new tiles with every matched pair. Choosing obvious pairs every time, such as those from the top levels, will often result in a loss by leaving more tiles uncovered.

3. In certain situations, obtaining matching tiles can be either impossible or highly unlikely. The key is to avoid getting into positions where this is likely to happen. Concentrate on matching tiles on horizontal lines, as these are usually more difficult to remove.

4. When you have 3 or more identical tiles free and matchable, match the pair that will free additional tiles. Matching the wrong pair can lead to unsolvable situations later.

5. It is imperative to react fast. Fast reaction means making the correct decision given the current situation as the result of previous decisions. You will be required to imagine your movements several steps ahead. The game might look playable now, but if you don’t look ahead and you make the wrong move, then the game could end with no solutions.

6. Some of the Mahjong characters on the tiles look quite similar, especially when you must quickly scan many tiles over and over. It is important to be able to distinguish all the tiles correctly and memorize where you last saw a certain piece.

All these tips may look intimidating the first time you play Mahjong solitaire, but don’t worry! This game actually is pretty easy to learn, but difficult to master. You will learn everything eventually, leading to less and less unsolvable situations after each successful game. So, give it a try and have a good one! :)