So this tells me that AFL appears to be a Yen play

This is quoted directly from the 2007 Annual Report:

"Aflac Japan’s premiums and most of its investment income are
received in yen. Claims and expenses are paid in yen, and we
primarily purchase yen-denominated assets to support yendenominated
policy liabilities. These and other yendenominated
financial statement items are translated into
dollars for financial reporting purposes. We translate Aflac
Japan’s yen-denominated income statement into dollars using
an average exchange rate for the reporting period, and we
translate its yen-denominated balance sheet using the
exchange rate at the end of the period. However, it is
important to distinguish between translating and converting
foreign currency. Except for a limited number of transactions,
we do not actually convert yen into dollars.
Due to the size of Aflac Japan, where our functional currency
is the Japanese yen, fluctuations in the yen/dollar exchange
rate can have a significant effect on our reported results. In
periods when the yen weakens, translating yen into dollars
results in fewer dollars being reported. When the yen
strengthens, translating yen into dollars results in more dollars
being reported. Consequently, yen weakening has the effect of
suppressing current year results in relation to the prior year,
while yen strengthening has the effect of magnifying current
year results in relation to the prior year. As a result, we view
foreign currency translation as a financial reporting issue for
Aflac and not an economic event to our Company or
shareholders. Because changes in exchange rates distort the
growth rates of our operations, management evaluates Aflac’s
financial performance, excluding the impact of foreign
currency translation."