in order to use hidden reserves battle action you need to be able to move the person to the battle field correct?
hidden reserves
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.
in order to use hidden reserves battle action you need to be able to move the person to the battle field correct?
No, assuming all other conditions (costs payable, required targeting and Presence) are met.
Hidden Reserves' ability says: Battle, (*): If this Follower is in your hand, target your Personality at any location. If he would be opposed, move him to the current battlefield and Equip this Follower to him.
To announce an action, one of the rules that must be satisfied is the Good Faith Rule. I'm asssuming you're concerned about this line in particular: To legally announce an action, a player must be able to: meet the conditions of any phrase beginning with “If” that starts the action’s effects (such as “If you are the Attacker, …”). The condition in Hidden Reserves' effects that is relevant to this rule is "If this Follower is in your hand." That is, you can't use the ability if the Follower is in play. The condition in the second sentence, "If he would be opposed," must be fulfilled for the movement & Equip effects in that sentence to occur, but it is not a condition you need to satisfy in order to announce the action.
However, if he would not be opposed, neither the movement nor the Equipping occurs, but you'll have still spent 3g, and the Follower is discarded after the action, as per step F of the Action Sequence: F. Finally, if the player took the action from a Strategy, or from another card type in hand, he or she discards it unless it is now in play.