Kaidan Dansu tectonics - blog 2

In my previous blog, I focused on the history of the kaidan dansu. This staircase chest was used for storing items and accessing floors above. Each kaidan dansu was made from a different type of Japanese wood and they were usually built in three parts. When it was tax collection time, homeowners would disassemble their staircase chests to hide the functional second floor. Each section of the kaidan dansu acted as a decorative piece of furniture, the middle appearing as a tansu. On its own, it served as large sculptures as well as interior partitions. The theme about which my artifact revolves, is that of tectonics.

It all began from the basic ladder concept of hashigodan. It was a standard tool for reaching heights. This type of ladder had a more comfortable stout design where boards were used for the vertical sides instead of poles and thick mortised planks were used as steps. Since this ladder was enclosed on three sides, it offered a great amount of stability. The ladder then evolved to the hakobashigo, which was wider in form and seemed more like a staircase rather than a ladder. It had a slanted wooden wall fixed beneath, which served as a safety stop in the event that someone would drop something. The creation of the hako kaidan followed, in which the principles of cabinets and stairs were combined. Depending on client needs, some would spiral upwards or simply stay as a straight staircase. They were built into the walls of the house and the drawers would be built separately in the space underneath. Finally, the kaidan dansu was created and it was a unique freestanding design that could be readily disassembled. Craftsman and carpenters no longer had to work on-site since pieces could be designed and constructed in their shops, yet be installed separately.

There are many different designs of kaidan dansu, all with different construction techniques. Below are three primary methods of construction:

What is commonly accepted as the most practical construction method, consists of a framework with recessed cuts (mortise) and projected pieces of wood (tenon) to which the panel, riser and thread are fastened. For design completeness, and to ensure the strength of the staircase chest, interior arrangements of steps are secured at the front, back and bottom.

In the second method of construction, the framework visually dominates the frontal view, however threads and risers are supported, secured and located behind these frames.

The final method of construction displays a framework throughout the step chest. This is considered to be one of the more attractive designs, however it also requires more labor. The framework consists of three mortised parts as well as tenon. In the sections where these pieces are joined to one another, there is a noticeable seam. Additionally, the thread and riser are inserted and enclosed within the frame. Lastly, the front and rear portions of the frame are made visible.