Shikaku rules

Rules

Divide the grid into rectangles such that each rectangle contains exactly one number and such that this number equals the area (i.e. the number of cells) of the rectangle.

Example

Here is a grid of Shikaku and its solution.

Shikaku example grid
Shikaku example grid solution

Solve the example online here.

History of Shikaku

According to the WPC unofficial wiki, Shikaku is a puzzle first published in 1989 in Nikoli. It was invented by Yoshinao Anpuku.

Star Battle Rules

Rules

Place some stars in the grid, no more than one by cell, such that the number of stars in each row, column and region equal the indicated number. Stars cannot share an edge or a corner.

Example

Here is an example of a Star Battle grid and its solution.

Star Battle example grid
Star Battle example grid solution

Solve the example online here.

History of Star Battle

According to gmpuzzle, Star Battle was invented by Hans Eendebak from the Netherlands in 2003 for the World Puzzle Championship.