威鎮諸魔 Awe Subduing All Demons
那小妖那裡知這個機關，即揭起衣服，貼身帶著個金漆牌兒，穿條絨線繩兒，扯與行者看看。行者見那牌背是個「威鎮諸魔」的金牌，正面有三個真字，是「小鑽風」。那小妖那里知这个机关，即揭起衣服，贴身带着个金漆牌儿，穿条绒线绳儿，扯与行者看看。行者见那牌背是个「威镇诸魔」的金牌，正面有三个真字，是「小钻风」。
逐句解 Line by line
How was that little demon to know the trick of it? He lifted his clothes at once, and there against his skin he wore a gilt-lacquered tally strung on a twist of silk cord, and pulled it out for Pilgrim to look at.
那裡知 has the second 那 as nǎ, the rhetorical interrogative — how was he to know. 機關 is the catch in a mechanism, and by extension a stratagem. 帶著 with 著 as zhe: the tally is worn continuously, next to the body, which is precisely why Pilgrim could not see it.
Pilgrim saw that the back of the tally was a gold plate reading Awe Subduing All Demons, and on the face were three plain characters: Little Borer of the Wind.
威鎮諸魔 is the motto stamped on the reverse — awe that holds all demons down — which is the sort of thing an institution puts on its identification. 小鑽風 is the man's grade, and 鑽 is zuān here, the level tone: to bore or drive through. 康熙 settles the split by name in 金部十九畫, quoting the 六書故 — departing tone for the tool, level tone for the verb. This is a rank built on a verb: one who bores through the wind, a scout.
The tally is described as an object first and read as a document second, which is how Pilgrim encounters it: a thing pulled from under a shirt on a cord.
Both faces matter. The back carries the organisation's motto and the front carries the man's grade, which is exactly how a modern identity card works — issuing authority on one side, holder on the other.
And the grade is a good joke. Little Borer of the Wind sounds like a title of terror and is in fact a job description for somebody who walks a route with a clapper.