詭託雷齋 The Feigned Thunder-Fast
行者道：「既如此說，賢郎甚有手段，實是敵得他過，方來請我吃唐僧的肉，奈何我今日還不吃哩。」妖王道：「如何不吃？」行者道：「我近來年老，你母親常勸我作些善事。我想無甚作善，且持些齋戒。」妖王道：「不知父王是長齋，是月齋？」行者道：「也不是長齋，也不是月齋，喚做雷齋，每月只該四日。」妖王問：「是那四日？」行者道：「三辛逢初六。今朝是辛酉日，一則當齋，二來酉不會客。且等明日，我去親自刷洗蒸他，與兒等同享罷。」行者道：「既如此说，贤郎甚有手段，实是敌得他过，方来请我吃唐僧的肉，奈何我今日还不吃哩。」妖王道：「如何不吃？」行者道：「我近来年老，你母亲常劝我作些善事。我想无甚作善，且持些斋戒。」妖王道：「不知父王是长斋，是月斋？」行者道：「也不是长斋，也不是月斋，唤做雷斋，每月只该四日。」妖王问：「是那四日？」行者道：「三辛逢初六。今朝是辛酉日，一则当斋，二来酉不会客。且等明日，我去亲自刷洗蒸他，与儿等同享罢。」
逐句解 Line by line
Pilgrim said: "Since you put it so — my worthy boy has real prowess, and is truly able to hold his own against him, and so has come to invite me to eat the Tang Monk's flesh — yet as it happens I shall not eat today."
Cornered into eating, he begins to improvise an excuse. 甚 in 甚有手段 is shèn, "considerable"; 得 in 敵得他過 is the light de, able to hold his own against him; 還 in 還不吃 is hái, still won't eat.
The demon king said: "Why not eat?"
The demon presses — and this is the crack through which the suspicion will enter.
Pilgrim said: "Of late I've grown old, and your mother is forever urging me to do a few good works.
The "mother" is 鐵扇公主, Princess Iron Fan, the Bull King's consort, brought in to give the excuse a domestic color. She will have a book's worth of trouble of her own with Wukong later on.
I thought, having done hardly any good, I would at least keep a few days of fasting."
The piety, invented on the spot. 甚 in 無甚作善 is shèn, "hardly any."
The demon king said: "I don't know, Father King — is it a perpetual fast, or a monthly fast?"
The demon probes the improvisation for detail, which is the natural thing to do and also exactly the wrong thing for Wukong. 長 in 長齋 is cháng, a perpetual fast.
Pilgrim said: "It is neither a perpetual fast nor a monthly fast; it is called the Thunder Fast, and comes to only four days a month."
So he invents a third kind. There is no such thing as a 雷齋, a Thunder Fast; he has made it up between one breath and the next. 長 in 長齋 is cháng.
The demon king asked: "Which four days?"
Which four? 那 in 是那四日 is the questioning nǎ.
Pilgrim said: "The three xin days, and the sixth as it falls.
And he answers with a calendar. Chinese days were counted by pairing ten heavenly stems with twelve earthly branches, a sixty-day wheel — rather like naming days by a repeating cycle instead of numbering them. 三辛逢初六 means the three days of the month carrying the stem 辛, plus the sixth. It sounds like real ritual lore because it is built out of real machinery.
Today is a xin-you day: for one thing, it is a fast day; for another, on a you day one receives no guests.
He even supplies a second rule to reinforce the first: today is a 辛酉 day, so it is a fast day, and on a 酉 day one receives no guests. That second rule is also invented. 朝 in 今朝 is zhāo, today; 當 in 當齋 is dāng, it falls a fast day.
Let us wait for tomorrow; I'll go and scrub and wash him myself, steam him, and share him with you children."
And the point of the whole performance: tomorrow. 兒 in 兒等 is ér, "you children"; 罷 in 同享罷 is the soft ba that makes it a proposal.
Cornered by the demon's insistence that he eat, Wukong invents a Thunder Fast of four days a month, complete with a fabricated calendar — the three days bearing the stem 辛, and a 辛酉 day on which one receives no guests — a virtuoso feat of extempore lying that puts the feast off until tomorrow. The excuse is dressed once more in domestic feeling: he has grown old, and the boy's mother keeps urging him toward good works. The comedy is in the sheer inventiveness, Wukong spinning plausible ritual lore out of nothing at conversational speed.
But the stall is what undoes him. To a demon who has eaten men all his life, a father who suddenly starts fasting is the one note that cannot be made to sound true — and Red Boy, already probing at it, hears exactly the discord that betrays a counterfeit. The next block opens inside the demon's own suspicion.