Rules: Fill the grid digits from 1 to 3, so that each region includes all digits exactly once. Same digits cannot touch each other, even diagonally. Outside clues show the sum of all numbers in the corresponding direction. Numbers should be read from left to right or top to bottom.
Background: Today, when I came home I was thinking about a Masyu variation. Last night I made a Total Masyu with symmetrical clues, but all clues were white, so I didn’t publish it. I wanted to keep on publishing Masyu variations on the blog for a while. I remembered Fred’s Masyudoku, that was a lovely puzzle type. Fred made one for Akil Oyunlari magazine, issue 77.
I had an idea when I went to buy bread 🙂 The grid had two loops with Masyu clues, one loop would use white and black circles same as Masyu, the other would use the colors as inverted. After deciding basic rule, a question appeared: Loops should cross each other, or should be placed separately into the grid. First one seemed better to me. However, I did something else. I drew a grid, created some regions… Voila! Summon was born. I like the type. It reminds me of a Japanese puzzle type. I wanted to give a Turkish name to the puzzle, but I couldn’t find a proper name. When I kept saying “Sum, sum, sum…” the puzzle replied to me “Ok, relax, summon is my name”. So this is the story.