Sanding & Polishing Progression

Pulling together the abrasives from Chapter 7 into an actual sequence, from raw wood to mirror gloss:

1. Wood surface: hand tools where possible, stop at 320-grit before the first coat. (Fine Woodworking)
2. Ground/shitaji layers: dry-polished flat after each of the three ji-nuri passes (Chapter 15).
3. Between naka-nuri coats: charcoal-and-water flattening, or 320–600 grit wet sandpaper. (Chapter 16, On Fountain Pens)
4. Pre-topcoat smoothing: progressing through 600–3000 grit wet/dry, then micromesh 1800–12000. (Tamenuri Studio)
5. Roiro polishing stage: fine charcoal (dozuri), then oil-based polishing powder, alternating with thin suriurushi coats (Chapter 20).
6. Final gloss: tonoko or migakiko powder worked by hand, finished with rapeseed/vegetable oil and deer-horn powder or fine titanium powder on the fingertips or palm — genuinely hand-polished, not machine-buffed, at this stage.

Every transition in this list is a real cure-and-inspect cycle, not a quick pass — which is the entire reason a finished roiro piece represents weeks to months of elapsed time even though the hands-on labor is comparatively modest.