Tricks "J"

Japan Air
A grab trick - the skater grips the toeside edge of the skateboard behind the front trucks with his front hand, twists his body away from the grip and drops his front knee towards the deck.

Jawbreaker
Instead of having your main, or strongest, arm on the bottom truck during the handstand, you have it on the top truck, making an already hard trick even harder.

Judo Air
The judo is a grab trick invented by Tony Hawk. It's a one footed nose grab where the front foot is extended to the toeside of the board.