The ulcer crater is still visible, but the margins become sharper and the diameter of the defect shrinks to about half or two-thirds of the A1 stage. Regenerating epithelium (new skin) starts appearing at the edges.

Sakitamiwa Classification Guide

The ulcer crater is still visible, but the margins become sharper and the diameter of the defect shrinks to about half or two-thirds of the A1 stage. Regenerating epithelium (new skin) starts appearing at the edges.