第二教 · Dai Nikyo
Uchi Mata 内股
Inner Thigh Throw
Mechanic
Tori's leg rises powerfully between uke's thighs, lifting one inner thigh skyward while the hands pull uke's upper body forward and around. Lifted at the middle and pulled at the top, uke rotates over the rising leg.
Analogy
You are stepping over the big dog asleep across the hallway, front foot already down on the far side, back leg still passing over him. He picks that moment to stand up, back end first. His rump rises under your inner thigh, that leg goes straight up toward the ceiling, and since you were already leaning into the step you go head-first over his ears.
Why it maps
The dog's rising back is tori's sweeping leg, lifting from the inside of one thigh, and your forward lean into the step is the hand-pull. Lift below, lean above, one leg skyward and the head goes over: that is uchi mata.