Sand the substrate to a flat, even surface
Before any adhesive or lacquer touches the wood, the kiji must be perfectly flat. Start with the edges: block each edge and sand it square and smooth, working around the full perimeter. Then move to the faces, using a sanding block held flat and moving in long, even strokes. The goal is to remove all tool marks, glue residue, and warping so that the surface reads as a single continuous plane. This is the most tedious step but the least technically difficult; it sets the geometric reference for every layer that follows.
When it is rightThe surface and all four edges are smooth, flat, and free of ridges or rough patches. Run a fingertip across the face: there should be no catch or variation in texture.
When it goes wrongRough spots or uneven edges left at this stage will telegraph through every subsequent coat and become visible in the finished piece. Recovery requires stripping back to the wood and re-sanding, which wastes all material already applied.
- The Korean workshop emphasises that a practice set of four MDF boards means sixteen edges to sand, and describes this as initially perceived as the hardest part but later recognised as the easiest compared to the lacquer work that follows.