Welcome to this fantastic collection of 100 bridges puzzles. The book contains 50 grids that are 9 x 9 in size, and are ideal for beginners, followed by 50 grids at a much larger 15 x 15 grid size, ideal for those who are experienced with bridges puzzles already, or have worked through the smaller puzzles. Here are the rules of bridges puzzles (also known as hashi puzzles). - The grid contains lots of circled cells containing numbers. These are known as islands. - Islands are connected by bridges. The number inside an island tells you how many bridges it has to other islands. - There cannot be more than two bridges between any pair of islands. Bridges must be either vertical or horizontal (not diagonal). Bridges cannot cross each other. - At the end of the puzzle once all bridges are drawn in, it must be possible to move from any island to any other island in the puzzle by walking across bridges from island to island. In other words, there are no isolated groups of islands. If you are uncertain, take a look at a couple of the solutions quickly to see what a valid solution looks like and how the bridges are connected.