Both are biographical asadoras about pioneering women in their fields. Asa is based on a leading Osaka businesswoman, while Tora-chan is based on one of Japan's first female lawyers and the first female judge. Both are also the closest asadora has gotten to a political, feminist stance. However, this doesn't hinder the viewing and only makes the stories more realistic.
Both are historical asadoras with strong women leads who have to fight for their chosen careers.
Both span a few decades and focus on a few generations of a family.
Both have strong female friendships that stand the test of social standing, time and lifes hardships.
Both have WW2 as a big turning point and they don't sugar coat the harsh reality of the time, while leaving the viewers hope for the future.