Inner thigh throw
Uchimata, or inner thigh throw, is classified as a leg technique in the nage-no-kata of Kodokan Judo. It often uses considerable hip action as well and some references therefore consider it a hip throw (such as Judo in Action by Kazuzo Kudo, 9th dan). It is one of the most successful throws in competition Judo at all levels, and it is difficult to defend against. In the photograph on the left the throw is being executed on the left side. The image to the right is a sculpture by Yoshiki Hasegawa of uchimata as performed in Sumo.
“A strong pull with both hands will insure you’re getting your left leg in far enough.”
…..Judo in Action by Kazuzo Kudo
Attacking
To perform the throw you must force your opponent off balance to the front. It is often done when your opponent takes a defensive posture with the legs spread and arms pushing strongly as the upper body is bent forward. You enter by pivoting or hopping in until you are standing on one leg between your opponent’s feet facing the same direction as the opponent. Sliding the other leg between your opponent’s legs you stretch it out and raise it up as you lean forward and pull your opponent onto your upper thigh. You will then bounce the opponent up and continue to turn and roll forward to complete the throw.
Books
Uchimata by Hitoshi Sugai is the best book available on this throw. It is an excellent examination of this powerful and popular tournament throw including many effective variations and follow-ups. It is also covered in less detail in Judo Unleashed and Black Belt Judo: Skills and Techniques by Neil Ohlenkamp.
Videos
Here are the best YouTube Videos.