纵横家是战国时代的政治、外交谋略家。分为苏秦“合纵”，张仪“连横”两派。站在洞口那位老者，就是纵横家的祖师爷——鬼谷子。鬼谷子精通天文地理、兵法、武术和奇门八卦，著有《鬼谷子》兵书十四篇传世 (民间称他为王禅老祖)。他创建了中国古代第一军校“战国军庠”，是真正的复合型人才。
鬼谷子有门徒500人，他的学生，从政治、外交、军事方面，对时局产生极大影响。苏秦、张仪，孙膑、庞涓，都是鬼谷子的高徒。这些人无一不是纵横天下，叱咤风云的大才。另有许多记载，表示毛遂、徐福、甘茂、乐毅、范雎、邹忌等也都师从鬼谷子。
淹城内城郭周长1500米，约3里，外城郭周长3500米，约7里，这里的面积大小正好和《孟子》中记载的“三里之城，七里之郭”相吻合。除此之外，淹城遗址的建城形制还有独特的神秘之处，从上俯瞰，淹城遗址就像是我们中国本土宗教道教的风水八卦图，据传，淹城的外城河最早有八条水溪，四个水门。经香港著名易学专家麦荣耀先生实地察看，认为恰好与《易经》中的八卦相吻合。依时间可以判定，淹城是历史上最早按照《易经》而建立的城池，因此又有了“中国风水第一城”的美称。
Legend says Laozi the grandmaster established this school. All its followers argued “the way of following nature” and “the importance of doing nothing”. In particular, Laozi himself and Zhuangzi separately composed Tao Te Ching: The Way and its Virtues and Zhuangzi: Wandering of the Way.
Laozi, also called Laodan, has been revered as the “Old One”. It is said this master later headed west on a black ox. Hangu Pass’s guard-in-chief Yin Xi, on the Sky-Watching Pavilion, suddenly saw a purple vapour rising in the east. He said to his underlings a sage must be coming here soon. As he had said, Laozi on an ox arrived slowly within 3 days. Yin Xi asked the master to leave him some words, otherwise he would not allow him to take leave. Then Laozi the Lord wrote Tao Te Ching, a short book of 5,000 characters influencing later China and the world at large.
战国时期出现，以博采众家之长为特色，由秦国丞相吕不韦一手创立。前方山体上的巨型书简上所雕刻的文字是杂家的代表作《吕氏春秋》。《吕氏春秋》是吕不韦和他的三千门客，历时近十年编写成的一部古代百科全书，是研究先秦历史、文化、政治、经济情况重要的依据。通过杂家也可以看到，到战国晚期，诸子百家的思想已经在一定程度上合流。
此处本是一带茅屋。相传兵圣孙武曾在此处隐居，躲避战乱，研究兵法。后人为纪念孙武，将他居住过的茅屋重新修缮。2019年，这处茅屋经再次修缮、改造，增加了品茶、书画、养生、休闲等功能，向游客开放。
Yancheng’s inner city sprawls 1,500 meters, about 3 li (a Chinese unit of length, 1 li=500 meters) while the outer city stretches 3,500 m or 7 li. Their areas fit well in with the relevant account in Mencius. Besides, the urban design has its own unique mystery. In a bird’s-eye view, the entire relic site looks quite like the Eight Trigrams according to Taoism and Geomancy. It is said the outmost moat had eight brooks and four watergates at the earliest time. Hong Kong based geomancer Mai Rongyao, having investigated the site, concluded the eight brooks represent eight trigrams in I Ching. The construction time shows Yancheng was the earliest city in the world to follow the mysterious geomancy. So, it is also called “First City of Chinese Fengshui”.
Founder of Mohism is Mo Di. Those engaged in debates were called “Mobian”. Those engaged in martial arts were called “Moxia”. The leader is called “Ju Zi”. Most of the Mohists come from lower status, with strict internal organization and discipline. “Those who kill will die for it and those who hurt will be punished”. They took promoting benefits and eliminating harm as educational purpose, and pay special attention to hard practice. Core ideas of Mohist School included “Universal Love”, “Anti-offense” and “Sparing Usage”, which advocate respecting talents and appointing capable people. Mohism and Confucianism were known as Famous Theories in the pre-Qin period.
In addition, Mohism studied mechanics, optics, logic and military attack and defense. Mohist’s Mojing (Mohist Canon) is similar to an encyclopedia, in which physical principles such as “Small Hole Imaging” were first put forward.
传说为老子所创，代表人物老子、庄子。以“道法自然”、“清静无为”为思想核心，代表论著《道德经》、《庄子》。
老子，即李聃，以其睿智，被尊称为“老子”。传说老子晚年乘青牛西去，函谷关的守城官尹喜在观气楼上突然发现东方升起一团紫气，就对旁边的人说，必定有贵人来。果然，不出3天，老子骑着一头青牛缓缓而来。尹喜要求老子留下他的智慧，作为放他出关的条件。于是老子在一块灵石上写下了五千言的《道德经》。
Originally, Sun Wu’s Thatched Cottage was an ordinary thatched cottage. It is said that Sun Wu, the soldier saint, once lived in seclusion here to avoid war and study the art of war in memory of Sun Wu. Later generations renovated the hut where he lived in memory of Sun Wu. The thatched cottage was repaired and transformed again in 2019, adding functions opening to tourists such as tea tasting, calligraphy and painting, health preservation and leisure.
淹城由外向内的第三道护城河叫子城河。子城河周长500米、宽约30米，环围子城。
子城，又称紫罗城，位于淹城遗址最中心，整体呈正方形。子城外围一周高高的土墙被称为子城墙，采用夯土堆筑的方法修筑而成。
传说子城是当年淹君治理朝政和生活的地方。考古发现的柱石洞等遗迹，证明了此处确曾有过大型建筑的存在。