Welcome! This is the official online shop of Hiroyuki Oka, a craftsman specializing in traditional Japanese puzzle boxes (Himitsu-Bako).

Difficult parts of Making the Aruki

Difficult parts of Making the Aruki
It was the first day of May, and it started with very heavy rain from the morning. The humidity was also quite high, so it was not the best day for woodworking. However, as planned, I worked on making the Aruki panels for the hexagonal boxes. I had some other things to do today, so this was the only woodworking task I focused on.

The photo shows the Aruki sliding panels I’m working on. In fact, the frame assembly is not fully finished yet, but about half of them are already assembled, so I made the Aruki panels to match those. I usually make them while checking against the frames, and using around 10 boxes as a reference is enough, so having half assembled is sufficient. Since there are slight differences between each box, I always adjust the size of the Aruki panels while checking them against about 10 frames. This is not something that can be measured exactly with numbers. Instead, I find the right balance by fitting them directly to the actual boxes. Especially with hexagonal boxes, variations tend to be larger compared to square puzzle boxes, so I need to be careful. Even if I make the panels to fit most of the boxes, there are always a few that don’t fit perfectly, so I adjust them one by one during assembly.

Among the five Aruki panels in this box, the most difficult part to adjust is where two panels meet at an angle, as shown in the photo. The panel with the groove is the one that moves at step 5, and the panel connected to it is the lid panel that moves at step 6. This lid panel must fit tightly into the step 5 panel, and at the same time, the back side of the lid panel must also fit perfectly against another panel (step 3). In other words, it has to fit precisely on both sides. If not, the lid panel will wobble left and right before the mechanism is even moved. In reality, it is impossible to perfectly adjust this for all boxes at once, especially because each hexagonal frame has slight differences. So the correct approach is to cut the panels slightly tight at first—just enough to barely fit. Then, if a panel is too long and cannot be installed, I carefully shave it down little by little. If I cut everything loose from the beginning so it fits easily, some panels will definitely end up too loose. Another challenge is the angle, as you can see in the photo. Because the panels meet at an angle, fine adjustments are more difficult compared to working with standard right-angled panels.After this, I plan to choose a dry day to attach the Aruki panels.
Have a great weekend! 😄