The east sonic is Sonic variation that involves a conical pass where twisted sonic and a pass is hybridised. Typically, the path of an east sonic goes 34-13.42-12 and has 1.0 rotations.

When noting down all possible twisted sonics between 34 and 12, there are four possibilities. Dot notation is very useful here to write down the exact way in which the pen passes through the fingers:

Tw sonic 34-12 = tw sonic 34-14.32-12
Inv tw sonic 34-12 = tw sonic 34-41.23-12
East sonic = tw sonic 34-13.42-12 = inv west sonic
West sonic = tw sonic 34-31.24-12 = inv east sonic

History

While the east sonic had been done for a long time before, it was first named east sonic by the French spinner Chronos in 2007. It was named that way because, when the motion of the ring finger is exaggerated, the finger positioning is reminiscent of the East Coast gang symbol.

While it is known that the name east sonic was made in 2007, and that west sonic originated later for its inverse, it’s unknown exactly when that happened. For example, in Daftsystem's Trick List on FPSB v2, there is east sonic but no west sonic. Instead, inverse east sonic is listed. In Japanese trick lists, only イーストソニック (east sonic) appears.

Variation

West Sonic

The inverse variation of the east sonic. It involves a twisted sonic starting in 34 and finishing in 12 in which the pen goes on the front of 3 and on the back of 2.

Tutorials

References

RPD Book