七十难曰∶春夏刺浅，秋冬刺深者。何谓也？然春夏者，阳气在上，人气亦在上，故当
浅取之。秋冬者，阳气在下，人气亦在下，故当深取之。
滑氏曰∶春夏之时，阳气浮而上，人之气亦然，故刺之当浅，欲其无太过也。秋冬之时
，阳
气沉而下，人之气亦然，故刺之当深，欲其无不及也。经曰∶必先岁气，无伐天和，此之谓
也。四明陈氏曰∶春气在毛，夏气在皮，秋气在分肉，冬气在骨髓，是浅深之应也。
七十一难曰∶经言刺荣无伤卫，刺卫无伤荣。何谓也？然针阳者，卧针而刺之；刺阴者
，先以左手摄按所针荣俞之处，气散乃内针。是谓刺荣无伤卫，刺卫无伤荣也。
滑氏曰∶荣为阴，卫为阳。荣行脉中，卫行脉外，各有浅深也。用针之道亦然，针阳必
卧针
而刺之者，以阳气轻浮，过之恐伤于荣也。刺阴者，先以左手按所刺之穴，良久令气散乃内
针，不然，则伤卫气也。无毋通，禁止辞。
七十难曰∶春夏各致一阴，秋冬各致一阳。何谓也？然春夏温，必致一阴者，初下针沉
之，
至肾肝之部，得气引持之阴也。秋冬寒，必致一阳者，初内针浅而浮之，至心肺之部，得气
推内之阳也。是谓春夏必致一阴，秋冬必致一阳。
滑氏曰∶致取也，春夏气温，必致一阴者，春夏养阳之义也。初下针即沉之至肾肝之部
，俟
其得气，乃引针而提之。以至于心肺之分，所谓致一阴也。秋冬气寒，必致一阳者，秋冬养
阴之义也。初内针浅而浮之，当心肺之部，俟其得气，推针而内之，以达于肾肝之分，所谓
致一阳也。此篇致阴阳之说，越人特推其理有如是者尔。凡用针补泻，自有所宜，初不必以
是相拘也。
《难经》第七十难说：春夏季节针刺要浅，秋冬季节针刺要深，这是什么意思呢？回答说：春夏时节，阳气上升于体表，人体的气血也趋向于体表，所以应当浅刺。秋冬时节，阳气下沉于体内，人体的气血也趋向于体内，所以应当深刺。
滑寿（滑氏）说：在春夏之时，阳气浮越向上，人的气血也是如此，所以针刺应当浅，目的是防止过度损伤正气。在秋冬之时，阳气沉降向下，人的气血也是如此，所以针刺应当深，目的是防止治疗不足。医经中说：“必须首先顺应岁气的变化，不要破坏人体与自然的和谐”，说的就是这个道理。四明陈氏说：春气存在于皮毛，夏气存在于皮肤，秋气存在于分肉之间，冬气存在于骨髓之中，这就是针刺深浅的对应关系。
《难经》第七十一难说：医经上讲“刺荣穴不要伤及卫气，刺卫穴不要伤及荣气”，这是什么意思呢？回答说：针刺属阳的部位（卫），要平卧针身进行刺入；针刺属阴的部位（荣），先用左手按压所要针刺的荣穴或俞穴处，待局部气血散开后再进针。这就叫做刺荣不伤卫，刺卫不伤荣。
滑寿（滑氏）说：荣气属阴，卫气属阳。荣气运行在脉管之中，卫气运行在脉管之外，二者所在的深浅层次不同。用针的道理也是这样，针刺阳分一定要平卧针身刺入，是因为阳气轻浮，如果直刺过深恐怕会伤及荣气。针刺阴分时，先用左手按压所刺穴位，停留片刻使气血散开再进针，否则就会伤及卫气。“无”通“毋”，表示禁止的意思。
《难经》第七十难又说：春夏各需引入一阴，秋冬各需引入一阳，这是什么意思呢？回答说：春夏气候温暖，必须引入一阴的方法是：初下针时深入至肾、肝所在的深层部位，得气后引导并持针以摄取阴气。秋冬气候寒冷，必须引入一阳的方法是：初进针时浅刺而浮提，至心、肺所在的浅层部位，得气后推针深入以摄取阳气。这就叫做春夏必致一阴，秋冬必致一阳。
滑寿（滑氏）说：“致”即取用之意。春夏气温，必须引入一阴，这是春夏养阳的道理。初下针时就深入至肾、肝所在的深层，等待得气后，引针向上提拉，直至心、肺所在的浅层，这就叫作引入一阴。秋冬气寒，必须引入一阳，这是秋冬养阴的道理。初进针时浅刺而浮提，处于心、肺所在的浅层，等待得气后，推针深入，以达到肾、肝所在的深层，这就叫作引入一阳。这篇关于致阴阳的说法，是越人（秦越人/扁鹊）特别推演其原理认为应当如此罢了。凡是用针进行补泻操作，自有其适宜的方法，起初不必被这种说法所拘束。
Chapter 70 of the *Nan Jing* (Classic of Difficult Issues) states: "In spring and summer, needling should be shallow; in autumn and winter, needling should be deep." What does this mean? The answer is: In spring and summer, Yang Qi (vital energy associated with warmth and activity) rises to the exterior, and human Qi also tends toward the exterior; therefore, one should needle shallowly. In autumn and winter, Yang Qi sinks to the interior, and human Qi also tends toward the interior; therefore, one should needle deeply.
Master Hua (Hua Shou) stated: During the time of spring and summer, Yang Qi floats upward, and human Qi behaves similarly; thus, needling should be shallow to prevent excessive depletion. During the time of autumn and winter, Yang Qi sinks downward, and human Qi behaves similarly; thus, needling should be deep to prevent insufficient treatment. The Classics state: "One must first accord with the seasonal Qi and not disrupt the harmony of Heaven and humanity," which refers to this principle. Chen Si from Siming stated: The Qi of spring resides in the hair and skin (Mao), the Qi of summer resides in the skin (Pi), the Qi of autumn resides in the muscle intervals (Fen Rou), and the Qi of winter resides in the bone marrow (Gu Sui); this is the correspondence for depth of needling.
Chapter 71 of the *Nan Jing* states: The Classics say, "When stimulating Ying (Nutrient) points, do not injure Wei (Defensive) Qi; when stimulating Wei points, do not injure Ying Qi." What does this mean? The answer is: To needle Yang aspects, insert the needle horizontally (lying flat against the skin); to needle Yin aspects, first press the intended Ying or Shu point with the left hand until the local Qi disperses, then insert the needle. This is called stimulating Ying without injuring Wei, and stimulating Wei without injuring Ying.
Master Hua stated: Ying Qi is Yin, and Wei Qi is Yang. Ying Qi circulates within the vessels, while Wei Qi circulates outside the vessels, each having its own depth. The method of using needles follows this logic as well. One must needle the Yang aspect horizontally because Yang Qi is light and floating; if inserted too deeply vertically, it may injure Ying Qi. When needling the Yin aspect, one must first press the acupoint with the left hand, wait for a while until the Qi disperses, and then insert the needle; otherwise, Wei Qi will be injured. "Wu" (No) is interchangeable with "Wu" (Do not), serving as a prohibitive term.
Chapter 70 of the *Nan Jing* further states: "In spring and summer, one must introduce a portion of Yin; in autumn and winter, one must introduce a portion of Yang." What does this mean? The answer is: In spring and summer, when the climate is warm, to introduce a portion of Yin, one initially inserts the needle deeply into the regions of the Kidney and Liver, obtains De Qi (arrival of needle sensation), and guides/holds the needle to draw forth Yin Qi. In autumn and winter, when the climate is cold, to introduce a portion of Yang, one initially inserts the needle shallowly and lifts it to the regions of the Heart and Lung, obtains De Qi, and pushes the needle deeper to draw forth Yang Qi. This is what is meant by introducing Yin in spring and summer, and introducing Yang in autumn and winter.
Master Hua stated: "Zhi" means to obtain or extract. The temperature is warm in spring and summer; to introduce a portion of Yin is the principle of nourishing Yang in spring and summer. Initially inserting the needle deeply to the region of the Kidney and Liver, waiting for De Qi, then guiding the needle upward to lift it until reaching the division of the Heart and Lung, is called introducing a portion of Yin. The air is cold in autumn and winter; to introduce a portion of Yang is the principle of nourishing Yin in autumn and winter. Initially inserting the needle shallowly and lifting it at the region of the Heart and Lung, waiting for De Qi, then pushing the needle inward to reach the division of the Kidney and Liver, is called introducing a portion of Yang. The theory of inducing Yin and Yang in this chapter is merely Yue Ren (Qin Yueren/Bian Que) specially deducing that the rationale is such. For all tonification and sedation techniques in needling, there are appropriate methods suited to the situation; one need not initially be bound by this specific rule.