第二教 · Dai Nikyo
Kouchi Gari 小内刈
Minor Inner Reap
Mechanic
As uke steps forward, tori hooks the advancing heel from the inside and slides it further along its own path while pushing uke straight back. The foot keeps traveling, the hips never arrive, and uke sits down between their own feet.
Analogy
You stride across a gleaming just-mopped supermarket aisle past the yellow warning sign. Your front foot hits the wet tile and keeps on going, sliding out far ahead of you while your body sits straight down behind it.
Why it maps
The slip extends the stepping foot along the exact direction it was already traveling, the same 'help your step keep going' action as the inner reap, leaving the hips unsupported and falling backward.