Useful Resources for Historical FX Rates
Tips: Each tax act may have unique regulations for determining the applicable foreign exchange rate. Generally, the Income Tax Act adopts the TTM (Telegraphic Transfer Middle rate) as of the transaction date.
The most comprehensive set of data available in excel format:
For a full set of FX rates available in Excel format, you can select the desired year and download it directly.
https://www.murc-kawasesouba.jp/fx/past_3month.php
The end of month FX rate at one sight:
https://www.supercostdown.info/kawasekinri3.html