Specifically Yen/USD or USD/Yen? I always take the long way. Thinking you will benefit (in the forward/futures) when Yen depreciates. Therefore you want the contracted rate of 100 Yen/USD to drop to 102 Yen/USD.
The sell party payoff = (contracted rate - spot rate) X NP
However when you put this in the formula, you will realize something is wrong (negative payoff despite in your favor). The exchange rate should have been inverted. Is there a rule of thumb to connect the statement “sell a forward on Yen” to assume the denominator is Yen (USD/Yen). Then it is intuitively correct and you can connect the payoff (sell party) formula.
In this case the asset is denom in Yen. So I should focus the currency as USD/Yen, Yen being the denominator.
I hedge the currency risk by selling Yen forward, hoping to benefit when 0.01USD/Yen (assume contracted rate) depreciates to 0.009USD/Yen (assume spot at time T).