第五教 · Dai Gokyo
Sumi Otoshi 隅落
Corner Drop
Mechanic
The famous 'air throw': no leg contact at all. The instant uke's weight settles onto a rear heel, tori drives their hands down toward that unsupported back corner, pushing uke's balance past the edge of their base. Gravity does the rest.
Analogy
A kid rocks their chair back onto its two rear legs, then one inch too far. There's a frozen instant where the chair is past the balance point: nothing is touching them, nothing pushed hard, but nothing on earth can bring them back. Over they go, backward into the corner.
Why it maps
The chair's rear legs are uke's rear heel: once the center of gravity drifts past that corner of the base, the fall is inevitable without any sweep, hook, or lift; balance alone was the weapon.