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

The Divider panel inside the box

The Divider panel inside the box
It rained all day today, continuing from the morning into the evening. Because the humidity was high, I avoided doing any work that required delicate adjustments — luckily, there wasn’t any such task scheduled today. Still, I was able to make progress on several other steps.

This morning, I worked on assembling the 5-sun 10-steps puzzle boxes with drawers. The assembly process for the drawer type is a bit more complex than usual, since it includes an internal divider to create the drawer space. This divider must be fitted while also putting together the frame panels at the same time. Both the frame panels and the divider require glue, so it’s important to apply it carefully. I apply glue along the edges of the panels and fit them precisely into the grooves, making sure it doesn’t get onto other parts.
Although the divider fits securely into the grooves of the side panels even without glue, I always apply it — otherwise, the panel can make a slight rattling sound when the box is moved.

When a puzzle box is operated, its mechanism causes the whole box to vibrate slightly. Each time that happens, the internal divider panel can also vibrate and make a rattling sound. That’s why I apply glue to fix the panel firmly to the main body.
It might seem like I could simply make the divider fit perfectly — just tight enough into the groove — but doing that would cause the dimensions of the frame’s shafts to become inconsistent. So, I make the grooves for the divider panel slightly looser on purpose.

This might be something that comes down to a craftsman’s intuition or sense of pride, but in this region, artisans really dislike it when panels inside a box make even the slightest rattling sound. I think it’s because such vibration can make the piece feel poorly made — almost like a cheap product.
When I was younger, during my training years, I was often told very strictly to make sure that the panels inside the box never vibrate. This practice isn’t limited to puzzle boxes — many other wooden crafts use similar panel structures, such as the base boards of trays, small boxes, and pen stands. In all of them, thin boards about 3 mm thick are fitted into grooves in the same way, and it’s considered important that they stay quiet and stable.

For that reason, I always apply glue carefully and firmly when attaching the divider panel. However, sometimes a little glue does seep out. As I mentioned before, once the excess glue dries, it becomes transparent and isn’t very noticeable — in fact, it even helps make the box stronger.
But any glue that seeps into the drawer space must be completely removed before it dries. Otherwise, it can catch on the drawer and interfere with its smooth movement. So, as always, I made sure to remove all of that excess glue this time as well.
*Starting today, I tried displaying the image at the top as the main visual 😄