Whenever a spell from the Lore of Yang is successfully cast, all friendly units within 6" of the caster gain the Armour Piercing (1) special rule until the start of the caster's next magic phase.
Source: Warhammer Armies Project: Unofficial 9th Edition
Whenever a spell from the Lore of Yang is successfully cast, all friendly units within 6" of the caster gain the Armour Piercing (1) special rule until the start of the caster's next magic phase.