Cherry Tansu with Twisted Dovetails

Tansu are traditional Japanese cabinets. They come in a huge range of shapes, sizes and styles, and many evolved from a need for mobile storage. Elaborate hardware and figured woods are pretty common features on high end tansu, while more modest cabinets seem to be more focused on simplicity and functionality. I’m really interested in the latter, and have had an opportunity to pick up a few simple old tansu here in Tokyo.

One of the cabinets that I picked up is pictured above on the left. Made of kiri (paulownia), and with just two sliding doors and a drawer, it’s a really simple and humble cabinet. The wood with it’s heavy texture, the design and proportions, and the basic hardware; I really love everything about it. It’s a great cabinet, but it’s storage capacity is limited, and I quickly filled it up with tools leading me to wish I had another. So I decided to make a replica of sorts, with a few minor upgrades.

Old Tansu and Wood Movement

Doors

Out of the 5 old tansu that my wife and I have, all of them have doors with the same type of construction as the old cabinet pictured here. The doors are frame-and-panel construction, except that the panel is glued to the stiles (vertical members of the doors) making them seamless. It makes for a beautifully simple door, but a huge fault of this type of construction is that the middle panel cannot move. It’s fixed to the side stiles and the stiles are joined to the rails (top and bottom door members). The usual result is that throughout the seasons as humidity levels change, the middle panel expands and contracts, and if the panel is glued to the surrounding frame it will usually be guaranteed to crack or split in some way. Surprisingly these doors have held up quite well, and are so far split free, though some of our other tansu haven’t faired so well.

Old Tansu Back and Drawer Bottom

Another area where wood movement has been ignored is in the back of the old tansu. The back is essentially a solid plank of kiri (paulownia) and nailed to the surrounding frame with bamboo nails. The drawer bottom is attached in a similar fashion, and both have developed splits as a result of the wood not being allowed to move. Below is a shot of the back of the cabinet. Along the sides you can see the bamboo nails, along with a mighty split running down the middle of the back.

Ignoring Wood Movement

Construction methods that don’t take wood movement into account are pretty common on the tansu that I have come across. One reason seems to be that traditionally homes in Japan weren’t heated during the winter, and in general the level of moisture in the air is pretty high. Meaning that wood wasn’t exposed to huge changes in humidity throughout the seasons, and craftspeople could get away with simply nailing or gluing boards without taking into account wood movement.

That’s a pretty common theory, and perhaps tansu may have faired better back in the day, but the reality is that nowadays most people are heating and cooling their homes to some extent throughout the year. In my own personal experience in our modestly heated and cooled Tokyo apartment, almost all of my antique tansu have splits in areas where the wood hasn’t been allowed to move. Many of the tansu had some splits when I received them, and I don’t know to what extent any of the damage may have changed since then, but ignoring wood movement is a clear problem. That said, regardless of heating/cooling, Japan is still a very high humidity environment so I’m guessing the level of splitting is far less than it would be in drier climates, like my home back in MN.

Finally, I’m also guessing that cost is a big factor to this whole discussion. Construction methods that allow wood panels to float and move require more time and effort to execute than simply nailing the wood in place. It seems pretty natural that to do so would raise the labor cost, etc. I would be curious to see how a really high end tansu is made. Maybe the craftspeople making high end tansu can afford to take more time with things like wood movement.

Wood Movement Upgrades

The above issues related to wood movement were my main points of focus for me when designing and building the cherry tansu. I took a bit of a departure from the original when dealing with wood movement in the doors, drawers and back of the cabinet.

Cherry Tansu Doors

The doors of the cherry tansu are styled like the old ones, but I’ve built them so that the middle panel can float within the door frame. I really like the simple style of the old tansu doors, so as much as possible I tried to maintain the same feeling. The proportions are the same and the panels are nearly flush with the frames. The main difference is that I didn’t glue the sides of the panel to the stiles, and left a small gap on each side of the panel to allow the wood to expand and contract.

Below right is an image and cross section of the new door, with the old on the left.

The doors slide side to side in a pair of grooves above and below the doors. I did the same thing on the White Oak Shoji Cabinet project. This system only allows for one door to be open at a time, but doesn’t require any hardware which I really like. I also like the design and shadow lines you get with one door set back from the other.

Drawer Joinery

The drawer for the old tansu uses bamboo nails to join the sides of the drawer to the front and back. The bamboo nails are a bit hard to see in the first photo below showing the connection between the drawer side and drawer front.

Here on the drawer side to back connection the bamboo nails are much more clear.

I used the same method for the cherry tansu’s drawer. I’ve also used this type of drawer joinery on projects in the past, and so far it’s worked out really well. It’s a really simple joint but relatively strong, and even on my old antique tansu which has seen a lot more use and years, the joints are still holding together. Not pictured is the upgraded drawer bottom joinery which allows the drawer bottom to float and move in a groove. A departure from the old tansu’s drawer bottom which was simply nailed in place with bamboo nails, and developed some splits as a result.

Tansu Shelving

The old tansu and the new have a matching series of shelves behind each door. Perfect Storage for smaller items. I believe the old tansu was used for storing utensils for preparing tea. Currently, both cabinets are being used for storing my collection of hand planes…. of which you can never have enough.

Twisted Dovetail Joinery

While I kept most of the details simple on the cherry tansu, one area where I played around a bit was the corner joinery. The original cabinet is joined at the corners using box joints that are pegged with bamboo nails.

I actually really like this style of joint a lot, and I’d like to do something similar on future projects.

But this time I felt like trying something completely new and used twisted dovetails to join the upper corners of the cabinet. There are a few different varieties of twisted dovetails seen in Japan, but the style below is perhaps the most straight forward, with an evenly spaced set of joints running across the corners of the cabinet. The finished result is pretty unique, and leaves a lot of people scratching their heads wondering how something like this goes together.

That covers most of the major features and design considerations behind this project. Thanks for following along on another furniture journey here. I’m hoping to share more details about some of the other old tansu I’ve been inspired by lately, including more design and construction details.

One of the benefits that I see for tansu like this is that given their small size they are easy to move around and can become stackable and rearrangeable. It offers a modular approach to furniture by moving away from large cabinets to smaller units that can be arranged by the user to fit their own needs and lifestyle. This whole project has really got me thinking about producing small tansu, and offering a few different designs and sizes for customers to use as they see fit. If anyone has any thoughts or suggestions I’m all ears.

-Jon