The last quarter of 2019 has been painful for yen bulls, but if history is any guide, good times may be just around the corner.

January has typically proved to be a favorable month for Japan's currency, bringing gains against the dollar in seven of the last 10 years. Some Tokyo-based strategists expect a repeat in 2020.

The case for a stronger yen is backed by a seasonal pattern that sees the greenback typically weaken at the start of the year, as global investors sell their dollar holdings to make fresh investments overseas, according to Credit Agricole CIB.