# Windmill: A Masyu Puzzle

The standard Masyu rules apply.

• Penpa link for solvers: git.io/JOnFI Apr 15, 2021 at 12:34
• @athin the rule link appears to be broken Jan 2, 2023 at 2:27

Solution

Step 1

Start with some basic deductions concerning circles that are next to a wall.

Step 2

Notice that we can't go through the white circles in rows 4 or 9 without making a loop so these must be crossed horizontally. Additionally, this forces the path descending from the top of column 3 to go left since going right would also force an issue in the top left corner. We can develop in the top left to get the following

Step 3

If the path goes through the black circle in row 4 to the left, then a little bit of development leads us to the following untenable position.

Hence, it must be that it goes to the right through this circle. Some more development in that region leads us to the following,

Step 4

If the path continues from the black circle in row 7 to the left, we can develop and get to the following untenable position.

Hence, the path must continue to the right from the black circle in row 7 and some more development leads us to the following position.

Step 5

From here, we see that the path must go horizontally after traversing the white circle in row 4. The deductions from there are reasonably straight forward.

• Great job and well done! You might need to point out why are they "untenable positions", especially the subtle one on Step 3 :) (and also FYI, black circle on line 6 has similar logic to the one on line 7 -- if that's somewhat helpful too for other solvers as well!) Apr 15, 2021 at 21:26