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.
A player, 11 November 2009
Togashi's Guidance:
Text Kami • Unique Dragon Clan players have no maximum hand size.
Reaction: After an action ends during which any Rings entered the discard pile from your hand or from your focused cards, if you are a Dragon Clan player, discard this card: Put one of those Rings into play or into your hand.
QUESTION: Can I discard Ring Of Water to move someone in/out of battle as my fourth battle action, then react with the Guidance to put it back in my hand, then immediately Play Ring Of Water?
Zen Faulkes (rules official), 11 November 2009
Togashi's Guidance:
Text Kami • Unique Dragon Clan players have no maximum hand size.
Reaction: After an action ends during which any Rings entered the discard pile from your hand or from your focused cards, if you are a Dragon Clan player, discard this card: Put one of those Rings into play or into your hand.
QUESTION: Can I discard Ring Of Water to move someone in/out of battle as my fourth battle action, then react with the Guidance to put it back in my hand, then immediately Play Ring Of Water?
"After an action ends" and "after an action resolves" have the same timing (http://rules.l5r.com/CE_Abilities_and_a ... ction_ends).
Because the Ring of Water enters play through a trait, it will always have to be played before the Reaction on Togashi's Guidance (http://rules.l5r.com/CE_Timing#Resolvin ... _conflicts).
Because you have to play the Ring before you can use the Reaction, and you can't "hold on" to an entering play trigger, this does not appear to work. You can get the Ring of Water into your hand, but the opportunity to play it will have passed. Just by a hair.