Although I did not know then that they were called Masu Boxes, I learned to fold these when I was nine. Not liking the creases across the lid left by the traditional folding method, or the uneven thickness in the sides, I created my own non-traditional variation.
I made dozens of boxes out of old calendars and cards and magazine pages. (My mother made me stop. I was filling the house with little boxes.)
Cut a square piece of paper.
Instead of folding the paper to establish the centre point, I draw a cross on one side of the square. It gets hidden by a layer of paper in the final structure, so it won’t show.
Fold each corner in to the centre, then open flat again.
Fold each corner again, this time to the point where the fold and the pencil line intersect. (Open flat after each fold.)
Fold each corner in to the intersection of the pencil line and the closest fold line. (Open flat after each fold.)
Your square should have a fold pattern that looks like this.
With a knife or a pair of scissors, cut along the pink lines shown in the image below.
With your paper oriented to match the diagram above, fold the top corner down to the centre and the bottom corner up to the centre. Fold the bottom and top up again to make the sides, then fold the flaps created by the cuts perpendicular to the sides
Take the remaining two sections and fold them over the flaps, locking them in place.
If you would rather make a traditional origami masu box with no cuts, Paper Kawaii has video instructions for a slightly simplified folding method.
She also has instructions for decorative lids here.
I made my yellow box out of 75 gsm/20 lb copier paper. The blue patterned box was made out of a page from a design magazine —slightly heavier paper than Time or People. I used a four inch square for the base and a four and a quarter inch square for the lid.
It’s a perfect size for holding playing pieces from Stern-Halma.