What the thread establishes
The answer.
Two practical routes emerge. The first, offered as a non-traditional shortcut, is a two-part epoxy (specifically JB Weld) filled into the break and finished with gold powder or gold paint; one commenter reports kitchen bowls repaired this way have endured years of daily use and dishwashing. The second is a genuine urushi-lacquer repair: the lacquer is mixed with gold powder, applied to one fracture face, the pieces are held in position for roughly forty minutes, and the joint is cured in a humid micro-environment. On food safety, the urushi route is said to be safe once fully cured but allergenic in its liquid state; the epoxy route is described by the manufacturer as non-toxic and microwaveable, though the manufacturer does not explicitly endorse ingestion. Neither path is confirmed by the thread to be free of long-term chemical leaching concerns.
—
What goes wrongThe most commonly reported failure is the repaired fragment peeling away after the lacquer has partially set, particularly if the piece is set down flat or jostled before the joint has fully cured. A secondary failure is squeezing out too much adhesive by pressing the fracture faces together too hard, which starves the joint of material. Both are recognised by the visible separation or the excess adhesive being forced out along the break line.
What recovers itIf the fragment has peeled off, the joint must be cleaned and the adhesive reapplied from scratch. To prevent recurrence, the piece should be stored in the same orientation it was held during assembly (break line facing up) and supported with a simple prop—such as a rolled ring of tape—so the fragment cannot shift while the adhesive cures.