Board Game Arena

The description is 'If you have fewer troops here than your opponent when the battle starts, each of your troops counts as ⚔⚔ instead of ⚔'.

As I attack another army with Hida O-Ushi and 4 troops against an opponent's army of 5 troops, my strength count was calculated as 4 instead of 8 (since 4 troops X 2). Is this a bug, or did I misunderstand how the ability works?

What was your Hero Strength calculated as?

You don't misunderstand it.

If you attack with 4 troops an army of 5, Hida O-Ushi should trigger.

A possible source of cancelling her ability is Bayushi Aramoro, the Scorpion Hero who asks to pay 1 influence to use hero beforehand.