This is a limited edition puzzle and was selected for the "7th Karakuri Idea Contest." Crafted in June 2015, each box of the set measures 3.54 x 3.54 x 1.58 inches or 90 x 90 x 40 mm. When the two boxes are combined correctly, FOUR secret spaces can be unveiled! The idea for this puzzle box stemmed from Yasuhiro Hashimoto and was hand-crafted by Hideaki Kawashima. Crafted in Walnut, Cherry, Walnut and Keyaki (Zelkova), it is visually appealing with beautiful contrasting colors. Will arrive in gift box and opening instructions.