I would label the rise of the Nikkei 225 since 2003 as a wave (B) of an expanded flat (ABC), in which the wave (B) consists of an expanded flat (W), an expanding triangle (X) and finally, a zigzag (Y).
I personally think there is sufficient wave count , or close to finish the zigzag (Y) pattern. The impending wave (C) does not bode well for the global financial market as well since Japan is the world's fourth largest economy.