# Yakuso

## Background

This puzzle was developed by Betrand Leplay and first appeared in the French puzzle magazine Multilogic; hence, despite its name, it appears to be of French origin.

## Puzzle and Goal

An unsolved puzzle consists of a rectangular grid. Some of the cells in the last row contain sums of the numbers in the same column; some of the other cells contain numbered clues.

The goal is to fill in all but the bottom row according to the rules.

## Rules

The solved grid must satisfy the following conditions:

In a given row, only 0 or one other number N may appear; N must appear N times.

No number (other than 0) appears in any two rows. For instance, if there are four rows, 4 must appear four times in one row, 3 must appear three times in another row, and so on for 2 and 1.

## Playable Online