Equipping Weapons to Matsuo is a Battle/Open action for you.
May I equip a weapon to him as a Naval action?
Yoritomo Matsuo
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.
May I equip a weapon to him as a Naval action?
No, as the Naval action "must come from a card in a Naval Personality’s unit," and the Equip ability is in the rulebook, not on the card.
On: Yoritomo Matsuo