Hashiwokakero

Hashiwokakero (Japanese Hashi o Kakero橋 を かけろ, dt Building Bridges ) is a logic puzzle which is published among others by the Japanese magazine Nikoli.

Regulate

Hashiwokakero is on a rectangular grid ( which is usually not printed ) played by any size. On some lattice sites are circled numbers between one and eight. The aim of the game is to connect all of these numbers by single or double lines together so that these lines form a contiguous path at the end of reached any number field.

The following rules apply:

• The lines are horizontal or vertical.
• The lines must not cross each other.
• Each line ends with a number.
• There are only single and double lines.
• Each key specifies how many lines begin and end at this point.

Will build the basis of the German translation of the term Hashiwokakero bridges to the number fields often referred to as islands, and the lines as bridges.

Normally, the solution or the searched path is uniquely determined by the given numbers.

History

The first appeared in Puzzle Communication Nikoli Hashiwokakero 31 ( September 1990), a forerunner of the puzzle appeared in issue # 28 ( December 1989).

Solution strategy

To solve Hashiwokakero trying typically first determine small fragments of the search path, which can then connect gradually to larger sections. For example, must start from a field with a number eight in all four directions double lines. Likewise, do not connect two fields with the number one if there are more number fields, since otherwise no coherent way possible. By logical reasoning can be so find some more rules.