This is a Nikoli original.
Puzzle and Goal
An unsolved puzzle consists of a rectangular (usually square) grid. Regions have been marked out, and some cells contain numbers.
The goal is to place a number in each cell to satisfy the clues.
The solved grid must satisfy the following conditions:
Each cell contains a number from 1 to n, where n is the number of cells in the region.
Each number in distinct within each region.
There must be at least m cells separating any two occurrences of the digit m in any particular rank (that is, 1s must have one cell between them, 2s must have two cells between them, and so on).
Hakyuu; Hakyuu Kouka; Seismic