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, 12 July 2007
Winter Warfare prevents Fusami from moving, does the 'and' prevent her from challenging the attacking enemy personality?
Reaction: After another player's target Personality assigns or moves to an army attacking you: Fusami moves to the target's location and challenges him. The challenge may be refused; if it is refused, bow the target and move him home. Destroy the loser.
Terrains cannot be played. Formations cannot be played. Actions cannot move units to or from battlefields. These effects last until the beginning of your second Events Phase from now.
Zen Faulkes (rules official), 12 July 2007
Winter Warfare prevents Fusami from moving, does the 'and' prevent her from challenging the attacking enemy personality?
Rules, Effects: "Effects are negated individually; negating one effect of an action does not automatically negate the others(.)"