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, 28 February 2015
If I Engage with Besieged Fortifications, would my opponent have the chance to counter it with Kaiu Built Defences?
Besieged Fortifications Fortifications at this Province give no bonuses and their abilities may not be used. Defending Personalities have -1F. Battle/Engage: Destroy a Terrain (if able). Put this Terrain into play.
Kaiu Built Defenses This Holding enters play unbowed. Interrupt, : Negate an Engage action. Battle, : Ranged 3 Attack
I am just unsure as to whether the terrains trait come into play before or after the Interrupt window.
Jon Palmer (rules official), 5 March 2015
If I Engage with Besieged Fortifications, would my opponent have the chance to counter it with Kaiu Built Defences?
Besieged Fortifications Fortifications at this Province give no bonuses and their abilities may not be used. Defending Personalities have -1F. Battle/Engage: Destroy a Terrain (if able). Put this Terrain into play.
Kaiu Built Defenses This Holding enters play unbowed. Interrupt, : Negate an Engage action. Battle, : Ranged 3 Attack
I am just unsure as to whether the terrains trait come into play before or after the Interrupt window.
Yes, as the Interrupt is taken prior to Besieged Fortifications being in effect.