The opening of the Asian session at 7:00 pm EST marks the start of the forex clock. You should take note that Tokyo session is sometimes referred to as the Asian session, because Tokyo is the financial capital of Asia.
One thing worth noting is that Japan is the third largest forex trading center in the world.
This shouldn’t be too surprising since the yen is the third most traded currency, partaking in 16.50% of all forex transactions. Overall, about 21% of all forex transactions take place during this session.