Here is a video showing how to fold a Masu Box (bottom and lid):
Masu Boxes are also very practical, as they can be used a gift boxes. To make them special, you can also add them dividers, as shown in the picture below.
The boxes and the dividers shown in the picture were folded with 6" (150 mm) squares of scrapbook paper (one for each bottom, one for each lid, and one for each divider).
The Masu Box Dividers were created by Bob Voelker. The instructions can be found in the book, OrigamiUSA - Origami Collection 2012.