"Aisuban" is a Japanese loanword from the German "Eisbahn", i.e., "Ice Road". This puzzle is available from Nikoli.
Puzzle and Goal
An unsolved puzzle consists of a rectangular grid divided into white and gray regions. There are some arrows on the grid.
The goal is to complete a path through the grid.
The solved grid must satisfy the following conditions:
The path must go through each arrow in the indicated direction.
The path may turn but may not cross itself in white regions.
The path may cross but may not turn in gray regions.
The path must go through each gray (ice) region at least once, but does not need to go through all cells.