先天法象 The Images of the Prior Heaven
行者聞言，近前答曰：「師父啊，你只知月色光華，心懷故里，更不知月家之意，乃先天法象之規繩也。月至三十日，陽魂之金散盡，陰魄之水盈輪，故純黑而無光，乃曰『晦』。此時與日相交，在晦朔兩日之間，感陽光而有孕。至初三日一陽現，初八日二陽生，魄中魂半，其平如繩，故曰『上弦』。至今十五日，三陽備足，是以團圓，故曰『望』。至十六日一陰生，二十二日二陰生，此時魂中魄半，其平如繩，故曰『下弦』。至三十日三陰備足，亦當『晦』。此乃先天採煉之意。我等若能溫養二八，九九成功，那時節，見佛容易，返故田亦易也。詩曰：行者闻言，近前答曰：「师父啊，你只知月色光华，心怀故里，更不知月家之意，乃先天法象之规绳也。月至三十日，阳魂之金散尽，阴魄之水盈轮，故纯黑而无光，乃曰『晦』。此时与日相交，在晦朔两日之间，感阳光而有孕。至初三日一阳现，初八日二阳生，魄中魂半，其平如绳，故曰『上弦』。至今十五日，三阳备足，是以团圆，故曰『望』。至十六日一阴生，二十二日二阴生，此时魂中魄半，其平如绳，故曰『下弦』。至三十日三阴备足，亦当『晦』。此乃先天采炼之意。我等若能温养二八，九九成功，那时节，见佛容易，返故田亦易也。诗曰：
逐句解 Line by line
The Pilgrim, hearing this, came forward and answered: “Master, you know only the moon's bright splendour, and your heart turns to your old home; you do not know that the moon's inner meaning is a rule and measure of the pre-celestial symbols.”
更不知 "moreover do not know," 更 read gèng; 先天法象 "the images of the Prior Heaven" (先天, the primordial state before differentiation); 規繩 "compass and marking-line," a governing standard; 行 read xíng. Wukong reframes the moon as an alchemical diagram.
“When the moon reaches the thirtieth day, the metal of its yang-soul is wholly dispersed, and the water of its yin-anima fills the disc; so it is pure black and without light, and this is called ‘the dark of the moon.’”
陽魂之金 "the metal of the yang-soul," 陰魄之水 "the water of the yin-anima" — the phases figure the interplay of yang (metal, 魂) and yin (water, 魄); 散 read sàn, 盡 read jìn; 晦 (huì) the dark of the moon, the month's last day.
“At this time it conjoins with the sun, and in the two days of the dark and the new moon, being stirred by the sun's yang it conceives.”
相交 "to conjoin," 相 read xiāng; 晦朔 "the dark (last) and new (first) days"; 有孕 "to conceive" — the yin moon quickened by yang.
“By the third day one yang appears, by the eighth two yang are born; the soul is half within the anima, level as a marking-line — and this is called ‘the first quarter.’”
魄中魂半 "half the yang-soul within the yin-anima," 中 read zhōng; 其平如繩 "level as a plumb-line," the half-moon's straight edge; 上弦 "the waxing (first) quarter."
“By the fifteenth day the three yang are complete and full, and so it is round and whole — and this is called ‘the full moon.’”
三陽備足 "the three yang fully provided"; 團圓 "round and complete"; 望 (wàng) the full moon, the fifteenth.
“By the sixteenth day one yin is born, by the twenty-second two yin; now the anima is half within the soul, level as a marking-line — and this is called ‘the last quarter.’”
魂中魄半 "half the yin-anima within the yang-soul," 中 read zhōng; 下弦 "the waning (last) quarter." The process now reverses, yin waxing as yang wanes.
“By the thirtieth day the three yin are complete, and again it is ‘the dark of the moon.’”
亦當晦 "is likewise the dark moon," 當 read dāng. The cycle closes where it began.
“This is the meaning of pre-celestial gathering and refining.”
先天採煉 "the gathering and smelting of the primordial (pre-celestial) essence" — the lunar cycle read as the alchemical harvesting and refining of the primal yang.
“If we can nurture the two-times-eight and bring the nine-times-nine to completion, then to see the Buddha will be easy, and to return to the old field easy as well.”
溫養 "to warm and nourish" (the elixir); 二八 "two-eights," the sixteen ounces (eight yin, eight yang) of a balanced whole; 九九 "nine-nines," the culmination of the yang number; 那 read nà, 佛 read fó; 故田 "the old field," the homecoming read as return to the primordial ground.
A poem says:
The verse-tag introducing Wukong's alchemical quatrain.
After the first quarter and before the last, the flavour of the medicine is even and balanced, its aspect complete.
前弦…後弦 "the first (waxing) and last (waning) quarters"; between them lies the full moon, when yin and yang are in equilibrium; 藥味 "the flavour of the elixir-medicine," the balanced primal energy.
Having gathered it, bring it home to refine in the furnace; set your heart on the work's fruit, and that is the Western Heaven.
採得 "having gathered it," 得 read dé; 爐裡煉 "to smelt in the crucible"; 志心 "to fix the mind"; 功果 "the fruit of one's effort." The pilgrimage itself is folded into the figure: the journey west is the refining of the inner elixir.
Wukong answers his master's lyric with doctrine. Where Tripitaka read the moon as beauty and homesickness, Wukong reads it as a diagram of inner alchemy (內丹): its monthly waxing and waning figure the interplay of yang (the "metal of the soul," 魂) and yin (the "water of the anima," 魄). He walks through the cycle — the dark moon when yang is spent and yin full; the conception of new yang as moon conjoins sun; the first quarter as one then two yang return; the full moon of complete yang; the last quarter as yin waxes again — each phase mapped to the internal process of gathering and refining the primal energy.
The vocabulary is that of Song-and-later internal alchemy, in which the adept's body is a crucible and the "medicine" is the primordial yang (先天), to be harvested at the right phase, nurtured ("warmed and nourished"), and brought to completion through the numerological work of the "two-eights" and "nine-nines." Wukong's closing claim reframes the whole pilgrimage: to perfect this inner work is itself to "see the Buddha" and to "return to the old field" — the journey west understood as the refining of the self.
The exchange stages the novel's characteristic layering of its Buddhist frame over a Daoist-alchemical substructure, and it quietly re-ranks the two pilgrims. Tripitaka, the poem's homesick author, is here the pupil; Wukong, elsewhere the impulsive troublemaker, is the one who reads the deeper "meaning of the moon." His verse makes the point exactly: the medicine gathered and refined in the furnace, the mind fixed on the fruit of the work — "that is the Western Heaven." The goal of the quest is relocated from a distant place to an inner attainment.