Riote gakun is a name for a manipulation where you place a gakun grip (yonkajo in aikido) on each of the opponent's wrists and use them to force him to go where you want him to. Gakun is a technique of hakkoryu jujutsu.
Grasp the back of his left wrist with your left hand. Let your thumb and little fingers loosely encircle the wrist joint. The ring and middle fingers assist in grasping. The index finger is extended and flexed as far back as you can make it go. This makes the "inside knuckle" protrude at the base of the index finger.
Keep your wrist stiff and straight. Angle your hand up away from his wrist so you can drive the "inside knuckle" into his arm, pinching the forearm muscles against the back of his radius bone. This hurts like hell once you catch on.
Make the same grip on the other side. Now press one hand down, driving the painful grip toward the floor. He'll try to go with it.
Turn the other hand over (his palm up) and use the gakun grip to drive his arm upward. This is equally painful, and paralyzes his response. One hand is going painfully downward, and the other painfully upward. He's torn.
You can push against his aching wrists and force him to back up. You can steer him like a wheelbarrow. You can even reverse the grips (exactly like the kata does), taking the upper hand down and the lower hand up, which helps to steer him where you want him.
The theory of the kata says that we're steering him up to the edge of the well so we can throw him in. That's my kind of theory.