Background Paragraph: Often, foreign exchange controls can result in the creation of black markets to exchange the weaker currency for stronger currencies. This leads to a situation where the exchange rate for the foreign currency is much higher than the rate set by the government, and therefore creates a shadow currency exchange market. As such, it is unclear whether governments have the ability to enact effective exchange controls.[1]. 
Story: On March 2015 Japans economy soared. There was a likelihood that the Japanese yen would rise in value. In the wake of this event, Japanese Government adjusted 
the price of Japanese Currency Yen in accordance with the going market price. On the other hand, at he same time, UK was having economic downturn. There was a likelihood that the UK Currency Pound Sterling would go down. Fearing public backlash, UK Government kept the price of the Pound Sterling at the same level. 
Question: Which currency would most likely not be exchanged in the black market, Pound Sterling or Yen?
Yen.