Hi, bad brained people. As you said there is no stone on the board. But as you can watch, some intersections are framed by triangles. Who said those are stones? As usual cases, it's not so difficult to understand it's an irregular board. Are you kids? And who said these problems are useless? Just researchable. See "Sensei's library". I didn't wanna make these problems useful in real games. Just researchable. You see or not.
