Masyu - Three Unpainted Circles
(Published on 4. June 2020, 07:00 by athin)
- Make a single loop with lines passing through the centers of cells, horizontally or vertically. The loop never crosses itself, branches off, or goes through the same cell twice.
- Lines must pass through all cells with black and white circles.
- Lines passing through white circles must pass straight through its cell, and make a right-angled turn in at least one of the cells next to the white circle.
- Lines passing through black circles must make a right-angled turn in its cell, then it must go straight through the next cell (till the middle of the second cell) on both sides.
The standard Masyu rules apply. However, exactly three circles should be painted black. You have to paint those circles black first so that the result is a uniquely solvable masyu.
Solution code: Row 2 (left-right) and Column 4 (top-down). Use L for cells with a bend in the loop, I for cells with a straight in the loop, and X for cells without loop.
Comments
on 6. June 2020, 02:14 by athin
@dm_litv Oh, in this context, "unpainted" means "not yet painted", therefore we want to paint 3 of them. However, now I realize why it's strange to read this with "not painted" definition...
on 5. June 2020, 21:31 by dm_litv
Why is so strange title of the puzzle? There are 4 unpainted circles, not 3.
on 4. June 2020, 11:30 by jessica6
the difference between this puzzle and a variable Masyu is that the first may have non-unique solutions until you choose the right circles. A variable Masyu must not have other solutions, or it would be a bad construction.
on 4. June 2020, 11:09 by athin
@Rollo Oh! Good to know, thanks!
on 4. June 2020, 10:26 by Rollo
We already have some puzzles like that. With advances search to 'Variables Masyu' you can find six of them. Very nice this one!
