A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
Archery Unit Battle: Bow this card: Ranged 4 Attack that is compared against the targeted card's base Force.
Base force is what is printed on the cards. Would a personality with a weapon (example: Modifications +4 Force) have that force against that Range Attack?
Would a personality with a weapon (example: Modifications +4 Force) have that force against that Range Attack?
Against such a Ranged Attack, Force bonuses and penalties are ignored, because as you said "Base force is what is printed on the cards." Thus a Personality with a base Force of 3 with a +5F Tsuruchi Daikyu and a +5F Chagatai's Armor attached and a -4F penalty from Temple of Purity still has a base Force of 3 and would be destroyed by such a Ranged Attack.