Another flashy catch, this time the ball is caught on the back of the hand in the gaps between your fingers. This is also called a back of the hand catch by those who state the obvious.
Place your hands palm down on a table & let your fingers spread out naturally. Keeping your palms on the surface lift your finger tips up as far as you can, now put your middle finger back down keeping the other fingers up. I call this the fork position. Place a ball so that it rests on top of the middle finger & is supported between the ring & index fingers. Wave your hands about a bit to get the feel of holding a ball in a fork.
Practise throwing one ball from hand to hand using only fork catches. Angle your forearms inwards so that if you touch the fingertips of your hands together your two arms form a right angle in front of you. Always keep your wrists straight. Just as you did with the Elbow Catch you will need to cushion the fall of the ball with your arm. With fork catches if you catch too low it is hard to hold your wrist back far enough to stop the ball rolling forward & off of your hand. Similarly if you catch too high it is difficult to keep your hands level to stop the ball rolling up your arm. Keep your arms up with your elbows sticking out to the side, insert your hand under the ball as it peaks & gently bring the ball to rest at just below chest height.
To throw from the fork position you need to do two things. Swing your upper arm, only a little, like a pendulum from the outside to inside, the swing gives the ball the horizontal movement to get from one side to the other. At the same time lift with the forearm to put in the vertical up & down movement. The two need to be put together into one smooth movement. If you try to throw with a sudden jerk the ball will at best fly off at an odd angle or else it will limply drop off of your hand. Aim for gentle control.
When you are comfy with one ball move up to three & try making the odd fork catch & throw. Make sure it is a controlled catch & throw. Don't just bat the ball off of the back of the hand & let the opposite hand correct the break in the tempo. A fork catch will not break the rhythm of the cascade when done nicely. Work up to performing fork catches with one ball every time, every right, every left & then every single ball (a Fork Cascade). For the fork cascade your hands & arms have to do a lot of movement to bring each ball under control before tossing it back. Keep your arms bent, your elbows up high & bend your fingers as far back as possible. After a while holding your fingers back will start to make the muscles in your arms ache at which point it is a good idea to stop & take a rest. Clench & unclench your fingers & loosely shake your wrists.
A single fork catch will largely go unnoticed by an audience, only juggling completely on the back of the hands will gain any attention. There are fork patterns definitely worth learning though, The Twist, The Toss Up, Two Ball Fork Exchange, Three Ball Fork Exchange & The Flick Off (all of which use the Fork/Palm Stack). You can use fork catches in more complex patterns such as Mills Mess or Boston Mess, but these tricks will only be truly appreciated by other jugglers!