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, 3 January 2012
I'm not sure if targeting Kyuden Otomo exp's tokens. If you count all pre-kolat edition cards to be influenced by stronghold immunity, can the tokens themselves still be targeted?
Yoritomo Komori
Battle: Destroy an opposing token. This ability may be used any number of times, but may not target tokens created during this battle.
Can this target the tokens on Kyuden Otomo exp? I'm pretty sure it can't because its technically not "on the opposing side", but More over can this one? Tengoku's Gates
Open: Bow this Shugenja to destroy a token. Open: Without bowing, destroy this Spell to destroy a number of tokens up to this Shugenja's Chi.
I think there are others, but this is the 1st that came to mind (other than the mantis and bat clan champions who say opposing). Its technically not targeting the stronghold.
Brook Cunningham (rules official), 4 January 2012
I'm not sure if targeting Kyuden Otomo exp's tokens. If you count all pre-kolat edition cards to be influenced by stronghold immunity, can the tokens themselves still be targeted?
Yoritomo Komori
Can this target the tokens on Kyuden Otomo exp? I'm pretty sure it can't because its technically not "on the opposing side", but More over can this one? Tengoku's Gates
I think there are others, but this is the 1st that came to mind (other than the mantis and bat clan champions who say opposing). Its technically not targeting the stronghold.
As of Emperor Edition rules, there is no more Stronghold immunity. Individual cards for the current format are being worded more carefully to prevent everything from happening that the rule prevented in the past.
As for older cards, the forthcoming Oracle of the Void will alter individual older cards' texts to compensate for the lack of the rule.
For now, and probably after that arrives as well, you are correct in that Yoritomo Komori cannot target a Stronghold's tokens because it's not opposing him, but Tengoku's Gates can.