Welcome!. Thank you for visiting. The Japanese puzzle box (Himitsu-bako) is made only of wood, environmentally-friendly products. This a one of traditional art work of Japan. The origin goes back even to the Edo and Meiji era (1800s) in Japan. It has been handed down by the very few craftsmen. I am crafting full-time these puzzle boxes by myself. I had training for 10 years and I'm crafting these Japanese puzzle boxes and Yosegi-zaiku for over 20 years. All items are made in my workshop and shipped to you directly. I will promise that all boxes are of good quality. My Puzzle boxes will move smoothly, because I will check and test all puzzle boxes before shipping. If you have a question, Please feel free to ask me anything. Thank you. Hiroyuki Oka" The puzzle box outside (Length) size : 1 sun (Mame / 4.3cm / 1.70inch) , 2 sun (6.0cm / 2.35inch) , 3 sun (9.0cm / 3.54inch) , 4 sun (11.6cm / 4.56inch) , 5 sun (15.0cm / 5.90inch) , 6 sun (18.0cm / 7.00inch) , 7 sun (21.0cm / 8.25inch).