Fun with Financial Data: Currency Exchange Rates

Someone posted some interesting photos from his trip to Japan in this January. One is delicious sushi sold at the roadside in somewhere, Kyoto, Japan.


In the top row, the one marked for 900 Yen looks exactly like the ones sold here in greocery store. I am wondering the price in US dollars.

900/FinancialData["USD/JPY"] gives $8.42, it is around 60% more expensive than the ones you can get here, however, it must taste much better.

One interesting thing is how much we can get if we convert 1 USD dollar to Japan Yen through the third currency.

FinancialData[{"USD",#}] / FinancialData[{"JPY",#}] &/@ {"HKD","EUR","GBP","CAD"}
{106.842, 106.625, 106., 106.947}

Direct exchange rate is 106.825.

USD->GBP->JPY: lost near 1% USD->CAD->JPY: gain tiny 0.1%

Is there a simple way to find a currency exchange chain "USD->..->... ->JPY" to maximize the gain over "USD->JPY"?