• USD/JPY slumped from 157.93 to 155.00 in Asia, on Wednesday, before partially rebounding

• Yen jumps suddenly as intervention speculation swirls

• The thin market exacerbated the move as Japan closed for "Golden Week" on Wednesday

• Drop took out the 155.50 Fibo, a 61.8% retrace of the 152.28 to 160.72 (February to April) EBS rise

• The 61.8% retracement is known by some as the "golden ratio", significant in determining direction

• A failure to register a Wednesday close below the 155.50 Fibo would provide encouragement to bulls

• 30-day log correlation between USD/JPY and EUR/JPY is back above +0.5 (pairs are moving in tandem)

Daily Chart


Correlation Chart


(Martin Miller is a Reuters market analyst. The views expressed are his own)