暗跟變蟹 How The Fan Was Won
行者笑道：「不必費心，我已得了手了。」牛王又問道：「你怎麼得的？」行者道：「那老牛與我戰經百十合，不分勝負。他就撇了我，去那亂石山碧波潭底，與一夥蛟精、龍精飲酒。是我暗跟他去，變作個螃蟹，偷了他所騎的辟水金睛獸，變了老牛的模樣，徑至芭蕉洞哄那羅剎女。行者笑道：「不必费心，我已得了手了。」牛王又问道：「你怎么得的？」行者道：「那老牛与我战经百十合，不分胜负。他就撇了我，去那乱石山碧波潭底，与一伙蛟精、龙精饮酒。是我暗跟他去，变作个螃蟹，偷了他所骑的辟水金睛兽，变了老牛的模样，径至芭蕉洞哄那罗刹女。
逐句解 Line by line
The Pilgrim laughed and said: "No need to trouble yourselves. I have already got it in hand."
Two 了 stacked on one short clause: the first closes the verb, the second closes the sentence. Both are the light le.
The Bull King asked again: "And how did you get it?"
得 is the plain verb "obtain" with 的 turning the whole question into a noun, so it reads dé. 怎麼 asks after something already done, unlike 怎生, which would push 得 into its lighter linking use.
The Pilgrim said: "That old bull fought me through a hundred bouts and more without either of us prevailing."
戰經百十合 uses 經 in its "pass through" sense; 合 is the bout or exchange, the novel's standard unit of combat. 分 in 不分勝負 is level-tone fēn, so the 不 before it stays bù.
"Then he left me and went off to the bottom of Green Wave Pool in Scattered Rock Mountain, to drink with a company of flood-dragon spirits and dragon spirits."
撇 is to fling aside, and the Great Sage uses it of being abandoned in mid-fight. 蛟 is the flood-dragon, a rank below the true 龍, and the pairing 蛟精、龍精 keeps the two apart.
"So I followed him in secret, changed myself into a crab, stole the water-parting golden-eyed beast he rides, took on the old bull's own shape, and went straight to Banana-Leaf Cave to gull the Rakshasi."
Every word of this is true, and he is saying it to the man he took it all from. 辟 is bì, to ward off — the beast parts the water in front of it — not pì. 剎 is chà throughout, the sound-spelling syllable of 羅剎, and it is wrong at all seventeen of this chapter's occurrences if read shā.
The Great Sage tells the whole thing, and he tells it well. The account is tight, ordered and entirely truthful — the fight, the desertion, the pursuit underwater, the crab, the theft of the mount, the second disguise, the cave. There is no boasting in it beyond the fact that he is telling it.
What makes the passage work is that every reader knows what the speaker does not. He is describing the robbery of the Bull Demon King to the Bull Demon King, item by item, and each loss is being recited to the man who suffered it. The Bull asked 你怎麼得的 and is getting a full, honest answer.
His own conduct is laid out plainly too, with nothing softened. He followed a man to a drinking party, stole his mount, wore his face and went to his wife's cave. He recounts it as a series of clever moves, which it was, and the chapter will spend the rest of its length collecting the bill.