This series of photo essays will document the preparation, construction, and set up of a simple swordsmith style kajiba (鍛冶場, forge building) from the ground up. The main inspiration for aesthetic, form, and technique is the humble Japanese inaka naya (納屋) style of a century ago.
The upper sections of the walls are tsuchikabe (土壁), a traditional infill technique used extensively in Japan. A mixture of natural clay, sand, and straw is applied over a tied bamboo lath (komai/kabekomai 壁小舞) attached to tie beams between the timbers.
Split Cedar Lath
A grid of ~3cm wide “thick bones” are first mortised into the timber frame and then ~2cm wide “thin bones” are tied to them using rope. A lattice pattern of horizontal and vertical elements provides plenty of purchase for the earth mixture to hang on to. In this case split cedar is used instead of split bamboo for the lath and scraps of old natural fiber rope are twisted apart and used as the binding twine.
Applying the Mud
The clay mixture is applied with a hawk and trowel and is about 1cm over the external lath with a reveal around the timber frame between 1 and 2cm. The rough arakabe mixture can be left as is for utilitarian purposes or can be coated with sandy middle layers and thin fine finish layers for decorative purposes (and increased weather resistance if the finish contains lime).
The next steps will be to finish the interior of the walls.