Combat Strength determines your odds of winning the sword figth.
Combat Strength is the player's swordfighting skill plus confidence and team spirit multiplied by energy.
Confidence and team spirit are not straight addition but instead are taken
T = TeamSpirit divided by 5
if Energy < T then ET = T else ET = Energy
C = Confidence divided by 10
Combat Strength = ( SwordFight + C + ( SwordFight * C / 100) ) * ET / 100
More info on Combat