Kani-basami (蟹挟), the crab scissors.

Nage-waza (throwing techniques), Yoko-sutemi-waza (side sacrifice techniques).
Required for: 4th Dan (black belt, British Judo Association); 5th Dan (black belt, British Judo Association).
Also known as: scissor takedown (english).

About
-----
A sacrifice throw in which tori leaps sideways and scissors uke's body between both legs, one across the waist and one behind the knees, felling uke like a cut stalk. It is documented here for recognition and history only: the technique is banned in competition and should not be practised in randori.

Key points
----------
1. Recognise it: both of the attacker's legs leave the mat and scissor the body
2. Banned in competition; attempting it is direct hansoku-make
3. Do not practise it in randori; the falling scissor risks serious knee injury

Reference pages elsewhere
-------------------------
Kani-basami on the IJF technique reference (International Judo Federation): https://judo.ijf.org/techniques/Kani-basami

From Waza Book: https://wazabook.com/techniques/kani-basami/