十难曰∶一脉为十变者，何谓也？
然∶五脏刚柔相逢之意也。假令心脉急甚者，
肝邪干心也；心脉微急者，胆邪干小肠也；心脉大甚者，心邪自干心也；心脉微大
者，小肠邪自干小肠也；心脉缓甚者，脾邪干心也；心脉微缓者，胃邪干小肠也；心脉涩甚者，肺邪
干心也；心脉微涩者，大肠邪干小肠也；心脉沉甚者，肾邪干心也；心脉微沉者，膀胱邪干小肠也。
五脏各有刚柔邪，故令一脉辄变为十也。
一脉十变，谓一脏一脉，其变有十也。五邪者，五脏六腑之邪也。刚柔，五脏为柔，六腑为刚。
相逢，谓脏邪干脏，腑邪干腑也。盖脏干脏则脉盛，腑干腑则脉微。假令夏主心，脉当浮大而散，今
反弦而急甚者，肝邪来干心也。此从后来，母乘子，为虚邪。小肠心之腑，脉当浮大而洪长，而微弦
急者，为胆邪，阳干于阳，阴干于阴，同气相求也。心脉虽洪大，当以胃气为本，今无胃气，故其脉
大甚也。此心自病为正邪，故言自干心也。小肠心之腑，微大者，较洪大则小，为小肠自病，故曰自
干也。缓者，脾脉乘心，故令心脉缓也。从前来，子乘母，为实邪，故言脾邪干心也。胃脉小缓，见
于心部，小肠心腑，故亦言干也。涩为肺脉，今见心部，是火不足以制金，金反凌火，从所不胜来为
微邪，故言肺邪干心也。微涩大肠脉，小肠心腑，故见于心部而言干也。沉者肾脉，心火炎上，其脉
本浮，今反见沉，是水来克火，从所胜来为贼邪，故言肾干心也。微沉者，膀胱脉也，小肠心腑，亦
见心部，故言干之也。此皆夏旺之时，心脉见如此者，为失时脉。推此十变之候，乃五行胜复相加，
故谓之五邪也。五脏各有表里，更相乘之，一脉成十，故曰十变也。有阳有阴，故曰刚柔也。于本位
见他脉，故曰相逢相干也。
越人以一心脏为例，余可类推矣。
Chapter 10 asks: What is meant by "one pulse transforming into ten variations"?
The response is: This refers to the interaction between the soft (Yin) and hard (Yang) aspects of the Five Zang organs. For example, if the Heart pulse is extremely rapid and tense (Ji Shen), it indicates Liver pathogenic factors invading the Heart; if the Heart pulse is slightly rapid and tense, it indicates Gallbladder pathogenic factors invading the Small Intestine; if the Heart pulse is extremely full and large (Da Shen), it indicates Heart pathogenic factors affecting the Heart itself; if the Heart pulse is slightly full and large, it indicates Small Intestine pathogenic factors affecting the Small Intestine itself; if the Heart pulse is extremely relaxed and slow (Huan Shen), it indicates Spleen pathogenic factors invading the Heart; if the Heart pulse is slightly relaxed and slow, it indicates Stomach pathogenic factors invading the Small Intestine; if the Heart pulse is extremely choppy (Se Shen), it indicates Lung pathogenic factors invading the Heart; if the Heart pulse is slightly choppy, it indicates Large Intestine pathogenic factors invading the Small Intestine; if the Heart pulse is extremely deep (Chen Shen), it indicates Kidney pathogenic factors invading the Heart; if the Heart pulse is slightly deep, it indicates Bladder pathogenic factors invading the Small Intestine.
Since each of the Five Zang organs has both hard (Yang/Fu) and soft (Yin/Zang) pathogenic influences, a single pulse position can thus manifest ten variations.
"One pulse, ten variations" means that for one Zang organ and its corresponding pulse, there are ten types of changes. The term "Five Pathogenic Factors" (Wu Xie) refers to pathogens from the Five Zang and Six Fu organs. "Hard" and "Soft" refer to the Six Fu organs being Hard (Yang) and the Five Zang organs being Soft (Yin). "Encounter" refers to Zang pathogens invading Zang organs, and Fu pathogens invading Fu organs. Generally, when a Zang invades a Zang, the pulse becomes excessive/full; when a Fu invades a Fu, the pulse appears slight/weak.
Assuming summer corresponds to the Heart, the pulse should be floating, large, and scattered. If it instead appears wiry and extremely tense, this is Liver pathogenic factors invading the Heart. This comes from the "later generator" (Mother) overacting on the "earlier generator" (Child), known as Deficiency Pathogen (Xu Xie). The Small Intestine is the Fu organ of the Heart; its pulse should be floating, large, vigorous, and long. If it appears slightly wiry and tense, this is Gallbladder pathogenic factors; Yang pathogen affects Yang Fu, Yin pathogen affects Yin Zang, seeking similar energies. Although the Heart pulse is vigorous and large, it must be rooted in Stomach Qi. Since Stom stomach Qi is absent, the pulse is excessively large. This self-disease of the Heart constitutes Righteous Pathogen (Zheng Xie), hence described as "self-invading the Heart." The Small Intestine is the Fu organ of the Heart; a slightly large pulse, compared to vigorous-large, indicates Self-disease of the Small Intestine, hence "self-invading." A relaxed pulse indicates Spleen pulse overacting on the Heart, causing the Heart pulse to appear relaxed. This comes from the "earlier generator" (Child) overacting on the "later generator" (Mother), known as Excess Pathogen (Shi Xie), hence "Spleen pathogen invading the Heart." The Stomach pulse is small and relaxed; appearing in the Heart position, and since the Small Intestine is the Heart's Fu organ, it is also described as "invading." Choppy is the Lung pulse; appearing in the Heart position, it indicates Fire failing to control Metal, with Metal counter-attacking Fire. Coming from the element that does not overcome it (but is overcome by it), it is called Minor Pathogen (Wei Xie), hence "Lung pathogen invading the Heart." Slightly choppy is the Large Intestine pulse; the Small Intestine is the Heart's Fu organ, so it appears in the Heart position as "invading." Deep is the Kidney pulse; Heart Fire flares upward, so its pulse should naturally be floating. If it appears deep instead, Water is overcoming Fire. Coming from the element that it overcomes, it is called Thief Pathogen (Ze Xie), hence "Kidney invading the Heart." Slightly deep is the Bladder pulse; the Small Intestine is the Heart's Fu organ, also appearing in the Heart position, hence "invading it."
These all occur during the season when Summer is prosperous. If the Heart pulse presents thusly, it is called an Out-of-Season Pulse. Analyzing these ten variations reveals the mutual overcoming and restitution of the Five Elements, hence termed "Five Pathogens." The Five Zang organs have interior-exterior relationships and mutually overact, forming ten variations in one pulse, hence "Ten Variations." There is Yang and Yin, hence "Hard and Soft." Seeing other pulses at the primary position is why it is called "encountering and invading."
Yu Ren (Bian Que) uses the Heart as an example; the rest may be inferred analogously.