Mokulock Bricks are a sustainable toy building block that comes from the Japanese Yamagata Prefecture. The region is mountainous and covered with lots of trees. However, since the trees cannot survive when they are too close together, the forest needs to be thinned regularly. Most of the thinned trees are used for building products and furniture, but the trees that are not suitable for those products are carved into these fun building blocks. You can learn more about the Mokulock story on their website.
Each package contains a variety of woods including Cherry, Bigleaf Magnolia, Maple, Birch, Hornbeam, and Zelkova. The blocks are not treated in any way - they retain their natural character without any stains or sealers, which makes them safe for anyone to play with.
One word of note: these blocks ARE NOT compatible with LEGO bricks. It is too bad, but you'll probably want to get rid of all that plastic once you get a chance to play with these beautiful wooden blocks.
Mokulocks are also available in 48-piece sets.