This week’s offerings are two Nikoli staples.
Masyu is a loop puzzle, where you try and join a loop in a grid containing white and black circles. The loop must pass through each of the circles; through a white circle the loop must go straight through, but then makes a 90 degree turn in one of the next squares. At a black circle, the loop makes a 90 degree turns, and then extends on in a straight line for at least two squares. See more here.
Nurikabe is an islands puzzle. You are given a grid of squares which must be coloured white or black. Each of the given numbers lies in an island comprised of the relevant number of white squares. Surrounding each island is a sea of black squares, subject to certain restrictions. Firstly the black squares are all connected, and secondly, given any 2×2 block of squares, at least one must be white. See more here.
#003 Masyu – rated easy