How Tall are the Main Characters from Journey to the West?

Last updated: 08-26-2023

A member of a Monkey King Facebook group I belong to posted a Chinese informational picture titled “Journey to the West: The Four Body Height Ratios of the Master and His Disciples” (Xiyou ji: Shitu siren shengao duibi, 西游记 师徒四人身高对比) (fig. 1). Each character is depicted with their correct corresponding height, ranging from Sun Wukong as the shortest to Sha Wujing as the tallest. The bottom of the picture provides some measurements:

The original novel describes Bajie’s body as being 1 zhang tall. Three chi is 1 meter. One zhang is around 3.3 meters. Sha Monk is 1.2 zhang, which is close to 4 meters. The Tang monk is 1.8 meters. The Lord Great Sage is 4 chi, or approximately 1.3 meters.

原著描述八戒身高一丈,三尺为一米,一丈是三米三左右。沙僧一丈二接近四米,唐僧一米八,大聖爺四尺,大约一米三。

The information is overgeneralized and at times conjectural, but I figured the picture would be interesting to my followers on Twitter. Little did I know that it would explode in popularity. As of this writing, my tweet has 940 likes (most of these received in a few days). This indicates that not many people were aware of the great height disparity between the pilgrims. I’ve therefore decided to write an article recording what Journey to the West actually says about each character’s height. 

I believe that the creator of the informational picture got their measurements from this essay, for it has the exact same title and very similar material (Zhongshi Damei Shenghuo [ZDS], 2020). I will use the claims therein to compare and contrast with the actual text from the novel.

Fig. 1 – The Chinese informational picture listing the pilgrims’ heights (larger version). I unfortunately don’t know who the original artist is. A reverse image search didn’t turn up anything. This page has the earliest appearance of the informational picture that I can find.

1. Measurements

ZDS (2020) uses a mixture of the ancient Chinese chi (尺) and zhang (丈) and the modern meter (mi, 米). The chi (and subsequently the zhang) varied at the local level at different times. During the Ming (1368-1644), when Journey to the West was published, the measurements equaled:

  • One chi (尺) = roughly 31.8 cm (12.3 in)
  • Ten chi = one zhang (丈)
  • one zhang (丈) = roughly 3.18 m (10.43 ft) (Jiang, 2005, p. xxxi).

Yes, the novel is set during the Tang (618-907), but many elements of the story (e.g. language, religion, mythos, martial arts, etc.) are filtered through the lens of the Ming. Therefore, it’s appropriate to use Ming-era measurements.

2. Heights

The characters are listed below from shortest to tallest.

(Note: I will be relying on the Wu & Yu (2012) translation. But since it uses “feet” instead of the original chi or zhang, I’ll alter the source throughout the article for more accuracy.)

2.1. Sun Wukong

See my previous articles discussing Monkey’s height (here and here).

ZDS (2020) states that Sun is “4 chi, that is less than 1.3 m [4.26 ft] or the same height as a child” (4 chi, yejiushi budao 1.3 mi, gen haitong yiban gao, 4尺,也就是不到1.3米,跟孩童一般高). But they miss an important distinction. The novel twice describes him as being “not four chi tall” (buman sichi, 不滿四尺), meaning that Monkey is an unknown height below 1.272 m (4.17 ft).

The phrase is first spoken by the Monstrous King of Havoc (Hunshi mowang, 混世魔王) in chapter 2:

When the Monstrous King saw him, he laughed and said, “You’re not four chi tall (emphasis added), nor are you thirty years old; you don’t even have weapons in your hands. How dare you be so insolent, looking for me to settle accounts?” (Wu & Yu, 2012, vol. 1, p. 128).

魔王見了,笑道:「你身不滿四尺,年不過三旬,手內又無兵器,怎麼大膽猖狂,要尋我見甚麼上下?」

The second is said hundreds of years later by the Great King Yellow Wind (Huangfeng dawang, 黃風大王) in chapter 21:

The old monster took a careful look and saw the diminutive figure of Pilgrim—less than four feet (emphasis added), in fact—and his sallow cheeks. He said with a laugh: “Too bad! Too bad! I thought you were some kind of invincible hero. But you are only a sickly ghost, with nothing more than your skeleton left!” (Wu & Yu, 2012, vol. 1, p. 408).

那怪仔細觀看,見行者身軀鄙猥,面容羸瘦,不滿四尺。笑道:「可憐,可憐。我只道是怎麼樣扳翻不倒的好漢,原來是這般一個骷髏的病鬼。」

Some readers may wonder why such a powerful character can be so tiny. This is because the novel describes Sun as a literal monkey. Refer back to this article for more information.

2.2. The Tang Monk

I have yet to formally write about Tripitaka‘s height.

ZDS (2020) suggests that the “Tang Monk should be about 1.8 m [5.90 ft]” (Tangseng yinggai zai 1.8 mi zuoyou, 唐僧应该在1.8米左右). This estimate is based around the size of a stone box used in chapter 49 to imprison him:

Pilgrim … mov[ed] towards the rear of the palace. He looked, and sure enough there was a stone box, somewhat like a trough that people use in a pigpen or a stone coffin. Measuring it, he found it to be approximately six chi in length (emphasis added). He crawled on top of it and soon heard the pitiful sound of Tripitaka’s weeping coming from inside (Wu & Yu, 2012, vol. 2, p. 347).

行者 … 徑直尋到宮後看,果有一個石匣,卻像人家槽房裡的豬槽,又似人間一口石棺材之樣,量量足有六尺長短。卻伏在上面,聽了一會,只聽得三藏在裡面嚶嚶的哭哩。

Six chi is 1.9 m or 6.25 ft. Tripitaka would obviously be shorter given the inside thickness of the stone walls, but the novel doesn’t provide such detailed information. This means that the 1.8 m estimate is conjecture. So, what other proof is there?

ZDS (2020) also cites a poem from chapter 54 as evidence that the Tank Monk is “tall and handsome” (yougao youshuai, 又高又帅):

What handsome features!
What dignified looks!
Teeth white like silver bricks,
Ruddy lips and a square mouth.
His head’s flat-topped, his forehead, wide and full;
Lovely eyes, neat eyebrows, and a chin that’s long.
Two well-rounded ears betoken someone brave.
He is all elegance, a gifted man.
What a youthful, clever, and comely son of love,
Worthy to wed Western Liang’s gorgeous girl! (Wu & Yu, 2012, vol.  3, p. 55). [1]

丰姿英偉,相貌軒昂。齒白如銀砌,唇紅口四方。頂平額闊天倉滿,目秀眉清地閣長。兩耳有輪真傑士,一身不俗是才郎。好個妙齡聰俊風流子,堪配西梁窈窕娘。

But, as can be seen, the verse mentions nothing about his height, only his beauty.

Hence, there isn’t enough information in the novel to officially say how tall Tripitaka is. But for those demanding some sort of answer, we can always speculate using real world data.

According to one study, out of a sample size of 28,044 Chinese men from 31 provinces/autonomous regions, the average modern height is 169 cm (5.54 ft). Additionally, this Chinese article references a study claiming that men from ancient times up to the Ming were between 165 cm (1.65 m or 5.41 ft) and 167 cm (1.67 m or 5.47 ft). This is obviously shorter than the 1.8 m suggested above.

Therefore, the most we can say is that the Tang Monk would be average historical height.

2.3. Zhu Bajie

I’ve written about Zhu Bajie’s height in the past (see here).

ZDS (2020) writes that Zhu’s “snout is 3 chi long” (zui chang 3 chi, 嘴长3尺). This is based on a descriptive poem from chapter 85:

A snout, pestlelike, over three chi long (emphasis added)
And teeth protruding like silver prongs
Bright like lightning a pair of eyeballs round,
Two ears that whip the wind in hu-hu sound.
Arrowlike hairs behind his head are seen;
His whole body’s skin is both coarse and green.
His hands hold up a thing bizarre and queer:
A muckrake of nine prongs which all men fear.

(Wu & Yu 2012, vol. 4, p. 149).

碓嘴初長三尺零,獠牙觜出賽銀釘。
一雙圓眼光如電,兩耳搧風唿唿聲。
腦後鬃長排鐵箭,渾身皮糙癩還青。
手中使件蹊蹺物,九齒釘鈀個個驚。

But, again, an important distinction is missed. Zhu’s nose is “over three chi long,” or larger than 95.4 cm (3.12 ft), which is over half the height of an average humanZDS (2020) says this measurement indicates that: “According to the laws of biology, (Zhu’s) body is approximately 3.5 m [11.48 ft]” (Anzhao shengwuxue de guilu, shenti yue 3.5 mi zuoyou, 按照生物学的规律,身体约3.5米左右). However, they never explain what laws they are referring to.

The only other information about Zhu’s size that I’m aware of appears in chapter 29. Upon entering a new kingdom, Tripitaka describes his two remaining disciples. [2] He starts with the pig spirit:

“My elder disciple has the surname of Zhu, and his given names are Wuneng and Eight Rules. He has a long snout and fanglike teeth, tough bristles on the back of his head, and huge, fanlike ears. He is coarse and husky, and he causes even the wind to rise when he walks (emphasis added) …” (Wu & Yu 2012, vol. 2, p. 51).

我那大徒弟姓豬,名悟能八戒,他生得長嘴獠牙,剛鬃扇耳,身粗肚大,行路生風 …

This tells us that Zhu has a large body capable of stirring the wind when he moves. But it’s important to note that Tripitaka’s subsequent dialogue assigns Sha Wujing a specific height (see below). This points to Zhu being shorter in comparison.

Therefore, just like the Tank Monk, there isn’t enough info to officially say how tall Zhu is. But we can again speculate using real world data.

My friend Barbara Campbell (blog) suggested that I use extinct prehistoric pigs as reference. A prime example is Megalochoerus homungous, which has been estimated to be 3.8 m (12.46 ft) long, 1.8 to 2.2 m (5.9 to 7.21 ft) at the shoulder, and up to 1,600 kg (3,527.39 lbs) (Uchytel, n.d.). A reconstruction by the paleo artist Roman Uchytel presents a towering creature with a head half as long as a man’s body (fig. 2). This is quite similar to the size of Zhu’s nose. Even with it’s head facing forward, a bipedal M. homungous would still be around 3.8 m (12.46 ft) tall. But as you’ll read below, this is too tall if Zhu is supposed to be shorter than Sha.

So how tall is Zhu? Your guess is as good as mine. But for those demanding some sort of answer, we can use human arm span to body height ratio, which is roughly 1:1. Using 1.8 m (5.9 ft), or the lower estimate for M. homungous‘ shoulder height, Zhu could be as much as 3.6 m (11.81 ft). But I am in no way comfortable with this estimate. It’s 100% pure conjecture, and I think it is still too tall.

Fig. 2 – A reconstruction of M. homungous by Roman Uchytel (larger version). Mr. Uchytel graciously gave me permission to use a watermarked version of his art for free. Please consult his website here.

2.4. Sha Wujing

I’ve previously mentioned Sha’s height in an article about Zhu Bajie’s appearance (refer back to here).

ZDS (2020) writes that Sha is “One zhangchi, nearly 4 m” (yizhang erchi, chabuduo 4 mi le, 一丈二尺,差不多4米了). This is based on Tripitaka’s continued dialogue with the foreign king in chapter 29:

“… My second disciple has the surname of Sha, and his religious names are Wujing and Monk. He is one zhang two chi tall and three span wide across his shoulders (emphasis added). His face is like indigo, his mouth, a butcher’s bowl; his eyes gleam and his teeth seem a row of nails” (Wu & Yu 2012, vol. 2, p. 51).

第二個徒弟姓沙,法名悟淨和尚,他生得身長丈二,臂闊三停,臉如藍靛,口似血盆,眼光閃灼,牙齒排釘。他都是這等個模樣,所以不敢擅領入朝。

This tells us that the monstrous monk is a whopping 3.816 m (12.51 ft) tall, with an exceptionally broad body.

Fun fact: Sha Wujing’s height is based on his giant antecedent, an obscure desert spirit appearing in the 7th-century biography of  the historical monk Xuanzang (on whom Tripitaka is based). The spirit comes to the cleric in a dream to admonish him for sleeping on the journey to India:

[Xuanzang] dreamed that he saw a giant deity several zhang tall (emphasis added), holding a halberd and a flag in his hands. The deity said to him, “Why are you sleeping here instead of forging ahead?” (based on Huili & Li, 1995, p. 28).

即於睡中夢一大神長數丈,執戟麾曰:「何不強行,而更臥也!」

“[S]everal zhang” would be 3 zhang (9.54 m or 31.29 ft) or more tall! That’s one big spirit!

3. Conclusion 

Journey to the West: The Four Body Height Ratios of the Master and His Disciples” is an informational picture that depicts the pilgrims with their correct corresponding heights. The bottom of the picture also provides measurements to supplement the illustration. These numbers were likely borrowed from ZDS (2020), an online article with the exact same name and very similar material. According to the essay, Sun Wukong is less than 1.3 m (4.26 ft), the Tang Monk is about 1.8 m (5.90 ft), Zhu Bajie is 3.5 m (11.48 ft), and Sha Wujing is nearly 4 m (13.12 ft). However, this information is overgeneralized and at times conjectural.

The original Chinese text of Journey to the West naturally gives more accurate information. But, unfortunately, the book only lists specific heights for two characters: Monkey is shorter than 1.272 m (4.17 ft) and Sha is 3.816 m (12.51 ft). As for the other two, not enough information is given for Tripitaka or Zhu to officially say how tall they are. However, speculating with real world historical height data suggests that the literary monk could be somewhere between 1.65 m (5.41 ft) and 1.67 m (5.47 ft), which is obviously shorter than the 1.8 m cited above. But even using prehistoric pigs as a reference, Zhu Bajie is the hardest to calculate since the novel indirectly implies that he is shorter than Sha. I used the lower end shoulder height estimate of the extinct M. homungous to suggest that Zhu could be as much as 3.6 m (11.81 ft) tall. But I think this is still too big.

On an interesting note, Sha’s great height is based on his giant antecedent, a desert spirit appearing in the historical Xuanzang’s 7th-century biography. The spirit is described as being 9.54 m (31.29 ft) or more!


Update: 08-26-23

Tumblr user digitalagepulao has drawn lovely versions of the JTTW pilgrims (fig. 3). And while some of their heights may differ slightly from those discussed above, the overall ratios are correct. I love the designs.

This is for digitalagepulao’s own “Expedition to the West au” (alternate universe) JTTW storyline based on a previous article of mine.

Fig. 3 – The height ratios for digitalagepulao’s JTTW character designs (larger version). Used with permission.

Note:

1) “Western Liang’s gorgeous girl” is referring to the Queen of Womanland.

2) The Tang Monk had previously expelled Monkey from the group in chapter 27 (Wu & Yu, vol. 2, pp. 26-28).

Sources:

Huili, & Li, R. (1995). A Biography of the Tripiṭaka Master of the Great Ci’en Monastery of the Great Tang Dynasty. Berkeley: Numata Center for Buddhist translation and research.

Jiang, Y. (2005). The Great Ming Code / Da Ming Lu. Vancouver, Wa: University of Washington Press.

Uchytel, R. (n.d.). Megalochoerus. Prehistoric Fauna. Retrieved from https://prehistoric-fauna.com/Megalochoerus.

Wu, C., & Yu, A. C. (2012). The Journey to the West (Vols. 1-4) (Rev. ed.). Chicago, Illinois: University of Chicago Press.

Zhongshi Damei Shenghuo. (2020, August 18). Xiyou ji: Shitu siren shengao duibi [Journey to the West: The Four Body Height Ratios of the Master and His Disciples]. Sohu. Retrieved from https://www.sohu.com/a/413598842_120113471

 

 

How Tall is the Monkey King? – A Debate

This was originally posted as a 03-03-2022 update to an existing article, but I decided to make it a standalone piece.

Last updated: 03-08-2022

In “What Does Sun Wukong Look Like?” I highlighted several sentences pointing to the Monkey King’s small stature (fig. 1 & 2). For example, one monster comments:

The old monster took a careful look and saw the diminutive figure of Pilgrim [Monkey]—less than four Chinese feet [buman sichi, 不滿四尺, 4.17 ft or 1.27 m] in fact—and his sallow cheeks. He said with a laugh: “Too bad! Too bad! I thought you were some kind of invincible hero. But you are only a sickly ghost, with nothing more than your skeleton left!” (Wu & Yu, 2012, vol. 1, p. 408).

This information was later used in the making of a youtube video called “10 Facts About Sun Wukong the Monkey King“. Fact number seven was that “He’s really short”, and I ended the section by saying: “That’s right! The Great Sage Equaling Heaven, the conqueror of the heavenly army … is the size of a child”. A Chinese viewer later left a thought-provoking comment on the video stating that I was wrong about Monkey’s size.

Fig. 1 – An accurate Monkey King (larger version). Drawn by my friend Alexandre Palheta Coelho (instagram and deviantart). Slightly modified by me to match what I’ve written here. For the original version, see here. Fig. 2 – A size chart comparing Sun to a six-foot human (larger version).

The Debate

Here, I will present the comment in full but interspersed with my responses:

Hello! I am a Wukong fan from China. I really enjoyed your video! I would like to say that the height of the Monkey King has been very controversial on the internet in China. The data and appearance depictions in classical Chinese novels can be somewhat exaggerated. Journey to the West is a mythological novel is even more so. For example, seventy-two transformations, a somersault that can travel one hundred thousand eight hundred thousand li respectively refer to infinite changes and fly extremely fast. Seventy-two and one hundred and eighty thousand are not exact numbers, so relying solely on data is not reliable. Besides, in addition to four feet, Wukong has also appeared other height data. For example, the earliest version of the Journey to the West, “世德堂本”, Chapter 21. “大圣公然不惧。那怪果打一下来,他把腰躬一躬,足长了三尺,有一丈长短。” “Our Great Sage was not in the least frightened. When the monster struck him once, he stretched his waist and at once grew three chi, attaining the height of one zhang altogether.”

This PDF scan (page 258) shows the original version of the novel did indeed read “grow three chi” (changle sanchi, 長了三尺) and not six like in the modern version (Wu & Yu, vol. 1, p. 408). I was surprised when this was brought to my attention.

One zhang minus three chi equals seven chi. In other words, the height of the Monkey King here was seven chi (Since the height unit in Chinese classical novels is based on the ancient system, 7 chi is around 5.5 feet). But in later versions and translations, “grew three chi” was changed to six chi. This has always been a point of contention. The figure of four feet (four chi) appears twice, both from the perspective of other monsters, such as the Monstrous King, who is three zhangs tall (around 24 feet). It may be possible that Sun Wukong is short in his eyes in comparison.

For those unfamiliar with ancient Chinese measurements, one zhang () equals ten chi (尺, i.e. “Chinese feet”) (Jiang, 2005, p. xxxi). The passage in question does imply that Monkey is seven chi tall. However, there are two problems. First, during the Ming (1368-1644) when the novel was published, one chi equaled approximately 12.52 inches (31.8 cm) (Jiang, 2005, p. xxxi). This would make Sun a whopping 7.3 feet (2.22 m) tall! I must admit that the chi varied at the local level, but I doubt the variations would lead to a nearly two-foot (60.96 cm) difference. Additionally, if we use the measures for the Tang (618-907 CE), when the story is set, a chi was 11.57 inches (29.4 cm), making Monkey 6.75 feet (2.06 m) tall. There was, however, a “small chi” (xiaochi, 小尺) at this time, which was 9.66 inches (24.6 cm) (Nienhauser, 2016, p. 405 n. 40). This would only make him 5.65 feet (1.72 m) tall. But I would question if the common folk reading the novel during the Ming were aware of and still using this truncated measure. Second, as written above, the figure for “not even four chi” (buman sichi, 不滿四尺, 4.17 ft or 1.27 m) appears twice. But it’s important to note that this estimate is made by two different characters at two different locations and times. The first is spoken in chapter two by the Monstrous King of Havoc (Hunshi mowang, 混世魔王) in the Water Belly Cave (Shuizang dong, 水臟洞) of the Mountain of Flowers and Fruit (east of the Eastern Purvavideha Continent) (PDF page 36; Wu & Yu, 2012, vol. 1, p. 128). This takes place over 100 years before Sun’s initial rebellion during the Han Dynasty (202 BCE-220 CE). And the second is spoken in chapter 21  by Great King Yellow Wind (Huangfeng dawang, 黃風大王) in the Yellow Wind Cave (Huangfeng dong, 黃風洞) of Yellow Wind Ridge (Huangfeng ling, 黃風嶺) somewhere in the Southern Jambudvipa Continent (PDF page 258; Wu & Yu, 2012, vol. 1, p. 408). This takes place sometime after his release from his 600-plus-year punishment under Five Elements Mountain during the Tang Dynasty (618-907 CE). Therefore, this seems like a more reliable measure—given the distance between themthan the ten minus three argument. I suggest the latter was actually a typo that later editions tried to amend by changing three to six. 

Another reason is that the author may be deliberately blurring the height of the Monkey King. Because at least in the story, the author describes Wukong according to the height of normal people. For example: Before Wukong learned Magic skills, when he could not change his height, he had robbed ordinary people’s clothes to wear. If Wukong was the height of a child, the clothes would hardly fit. When Wukong set out on his journey to the west, he once wore the clothes of Tang Monk. Wukong could carry the Taoist priest changed by the Silver Horned King (if he was a child height this would be very difficult).

These are good points, but a 7.3-foot tall Monkey wouldn’t be able to wear the clothing of the aforementioned people either. Conversely, tucking in or rolling up clothing wouldn’t be out of the question. And carrying a priest wouldn’t be a problem for a small-statured hero capable of hoisting the weight of two cosmic mountains while running at meteoric speeds.

In the same chapter, the Tang monk sitting on the horse can pull Wukong’s tiger skin skirt. Wukong can easily grab Eight Rules’ ear. In the Bhikṣu Kingdom, Wukong once exchanged clothes with Tang monk, etc.

Horses are tall animals, so the Tang Monk would’ve probably fallen off before even grabbing the skirt of an adult-sized Sun Wukong. I look at this as something that sounds good on paper until it’s tried in real life.

I think even a 5.5-foot tall Monkey would have problems grabbing the ear of Zhu Bajie, who is likely 10 feet (3.05 m) tall or more given his three chi (3.13 ft / 95.4 cm) snout (PDF page 108; Wu & Yu 2012, vol. 4, p. 149) and giant body that “causes even the wind to rise when he walks” (PDF page 367; Wu & Yu 2012, vol. 2, p. 51). Either way, jumping would be involved, making this irrelevant.

And just because Sun might be smaller doesn’t mean he wears child-sized clothing. I believe the first instance of sharing clothes happens in chapter 14: “Pilgrim … noticed that Tripitaka had taken off a [robe] made of white cloth and had not put it on again after his bath. Pilgrim grabbed it and put it on himself” (PDF page 174; Wu & Yu, vol. 1, p. 313). He seems to wear whatever is available to him.

In China, there is another speculation about Wukong’s height: monkeys are usually hunched over. Wukong is four chi tall when bent over and seven chi tall when standing upright.

I studied primates in college. Monkeys usually walk on their palms (palmigrade) (fig. 3) and only stand when foraging, fighting, or carrying things. But I don’t recall the novel ever mentioning Sun traveling on all fours (please correct me if I’m wrong). Therefore, he likely walks on two legs. In this case, as stated, monkeys have a hunched posture when standing. They can’t stand straight because of mechanical limitations in their skull, spine, hips, legs, and feet (my previous essay on hominids applies to monkeys as well). One could argue that Monkey can overcome these limitations with his immortal body, but this definitely wouldn’t give him three more chi of height. For example, here’s a macaque standing at full height (fig. 4). As can be seen, straightening the head, spine, and legs would only give a handful of inches or centimeters.

Fig. 3 – A macaque skeleton in its natural posture (larger version). Fig. 4 – A young macaque male standing (larger version).

And as stated in this article, Sun shares all of the hallmarks of a macaque, including a “furry, joweless face with fiery eyes, a broken or flat nose, a beak-like mouth with protruding fangs, and forked ears”. This likely includes a smaller stature.

Of course, there is no doubt that he is very thin, and is definitely the shortest one in the scripture takers, but at least, his height is more like that of a shorter adult than a child. The role of Sun Wukong is a combination of human nature, monkey nature, and divinity. The author may be deliberately obscuring his height. Therefore, when describing daily life, Wukong is the same height as normal people, but in the eyes of other demons, he is more prominent in the shape of the monkey. And he has the divine power to change his height at will. Sorry for my bad English, really enjoyed your video!

I will concede that four chi is a rough estimate, so he might be slightly shorter or even taller than this. Either way, he’d be far below average human height.


Update: 03-06-22

Chapter 20 includes a scene where Monkey refers to his stature: “A person like me, old Monkey, may be small but tough, like the skin around a ball of ligaments!” (PDF page 246; Wu & Yu, 2012, vol. 1, p. 395).


Update: 03-08-22

Above, I suggested that the ten minus three argument was a typo. But there might be a numerological explanation. Qing-era scholar Wang Xiangxu (汪象旭, fl.1605-1668) borrowed from the Daoist philosophy of Zhang Boduan (張伯端, 987?-1082) by applying his “three fives equal one” (sanwuyi, 三五一) five elements concept (fig. 5) to numbers appearing in the novel. As Shao (1997) explains:

One set of five consists of wood (3) and fire (2). Wood in the east produces fire in the south. The second set is that of metal (4) and water (1). Metal in the west produces water in the north. The third is earth in the center whose number is five. The whole business of the “gold elixir” is to integrate all three sets of five to produce one—the gold elixir (pp. 16-17).

Shao (1997) goes on to explain the numeric significance of the dharma vessel constructed from Sha Wujing’s 9-skull necklace and the heavenly gourd in chapter 22: 

Wang Xiangxu shows a keen eye for the “one” gourd and “nine” skulls which make a perfect “ten”—the number for the completion of earth. However, it is not the numbers that attract him, but what they indicate—that the gold elixir is creation—a process that involves the integration of all the five elements—not unlike the creation of the universe (p. 18).

Therefore, three (wood) and seven (fire) may be a reference to the completion of ten (the golden elixir) in Daoist numerology. If this is true, even the later switch from three to six still matches this (refer to fig. 5).

Fig. 5 – A chart explaining the three fives (larger version). From Shao, 1997, p. 17.

Sources:

Jiang, Y. (2005). The Great Ming Code / Da Ming Lu. Vancouver, Wa: University of Washington Press.

Nienhauser, W. H. (2016). Tang Dynasty Tales: A Guided Reader. Singapore: World Scientific.

Shao, P. (1997). Monkey and Chinese Scriptural Tradition: A Rereading of the Novel Xiyouji (UMI No. 9818173) [Doctoral dissertation, Washington University]. Available from ProQuest Dissertations and Theses database.

Wu, C., & Yu, A. C. (2012). The Journey to the West (Vols. 1-4) (Rev. ed.). Chicago, Illinois: University of Chicago Press.