Logic Masters Deutschland e.V.

The difficulty of this puzzle may vary greatly depending on your experience with loop puzzles. If you've never solved a loop puzzle, you might want to spend a moment to try and discover some "secrets" of the genre (akin to the better-known secrets of yin-yang puzzles).

• Nurikabe-cave: shade some cells so that each orthogonally connected group of shaded cells touches the edge of the grid, and all unshaded cells form a single orthogonally connected group. Every 2x2 area contains at least one shaded cell.
• Directed loop: draw a loop through the centers of some cells which only moves vertically or horizontally, and does not branch or cross itself. Additionally, the loop passes over every arrow in the indicated direction, must travel straight through shaded cells, and must turn 90 degrees through unshaded cells.

The name of the puzzle is a reference to a classic Japanese novel, 「銀河鉄道の夜」. The first few drafts of the puzzle had many arrows positioned in spiraling "galaxy" motifs, so I thought a loop through the clues was like a railway through the universe. However, in the final puzzle, almost all traces of galaxies have disappeared!