第五教 · Dai Gokyo
Yoko Guruma 横車
Side Wheel
Mechanic
When uke is bent forward over tori, tori throws a leg through, drops onto their own side, and uke's forward momentum carries them wheeling in a big circular arc over tori's fallen body, landing on their back beyond it. Tori's body on the ground is the axle of the wheel.
Analogy
Stumbling forward, you run into a big barrel lying on its side right at your knees. It rolls as you hit it, your hips ride up over the curve, and you wheel through one full arc over the top, landing flat on your back on the far side.
Why it maps
The lying barrel is tori's dropped body: a round axle on the ground that catches a forward-committed mass and turns its momentum into one big circular throw over the pivot.