About Yazudo

What is Yazudo?

Yazudo (矢図道) is a logic puzzle game. The name combines the Japanese characters for "arrow" (矢, Ya), "diagram" (図, Zu), and "way" or "path" (道, Do).

This puzzle is known by several other names, including:

• Pointer
• Japanese Arrows
• Zeiger (German)
• Nummernpfeile (German)

History

According to Donald E. Knuth, this puzzle type was first published in 1992 by Masanori Natsuhara as part of Puzuraa magazine.

How to Play

The rules are simple but allow for complex logical deductions:

• A number must be placed into each arrow.
• The number must be equal to the count of distinct numbers that the arrow specifically points at.

Controls:

• Use the numpad or digit keys to enter numbers.
• Use Pencil Mode to take notes. You can hold CTRL to temporarily switch to pencil mode while in pen mode.

Example Puzzle (4x4)

Puzzle

Solution

2

1

0

0

2

1

2

1

1

1

2

2

3

2

1

2

Tips for Starting Out

• Look for edges: Start with arrows pointing outside the grid; they must always be 0 because they point at nothing.
• Single targets: Arrows pointing at only one other arrow are also great starting points.
• Limited visibility: Look into arrows that have only a few free cells ahead of them in their path. This limits the possible numbers that can go into that arrow.