The earliest salt extracted by hand in ancient times was probably sea salt.
Ancient records, the Yandi (said Shennong's) Cusha's pioneered the use of seawater to cook salt, known as the "Cusha for cooking salt".
Su Sha's people, just a legendary figure, in fact, salt with seawater, should be living in the ancient ancestors of the sea after a long period of exploration and practice to create.
Perhaps Cusha's method of boiling salt was popularized and later generations attributed the invention of harvesting sea salt to him.
Pool salt: Lake salt, also known as pool salt, is found in inland salt lakes that are able to naturally produce crystallized salt due to the dry climate.
Historically, the ancient salt ponds of Hedong were known as "Xieyan", "Luyan" or "Hedongyan" because they naturally produced salt by evaporation from the wind and the sun.
The Hedong Salt Ponds appeared in historical records at a very early stage, and the history of salt mining in the ponds may not be any later than that of sea salt.
The Charkhan Salt Lake and Chaka Salt Lake in Qinghai Province are now producing this kind of salt.
The pool salt has the characteristics of natural crystallization, Jin Wang Zhu "Luodu Fu" cloud, "salt pools in Hedong, jade clean ice fresh, do not bother to cook the Wo, into the natural," is to say that the pool salt does not need to be boiled by fire, the natural can be obtained.
Hedong Salt Pond is located in the Yellow River Basin, living in the Yellow River Basin of the ancient ancestors, should be very early contact with this natural salt.
Now it is difficult to determine the discovery of pool salt and sea salt and consumption of which came first, because sea salt can also be stagnant shallow sea water by the wind and sun, due to evaporation and natural crystallization.
Ancient peoples living by the sea would also have discovered and consumed this natural sea salt that crystallizes naturally.
Naturally occurring pool salt and sea salt, as well as rock salt exposed on the surface of the ground, salt springs that naturally overflowed and drained, and earth salt that was readily available, as long as there was human activity in the area where these natural salts were produced, the first people would always have discovered it sooner or later.
It is only because of the long period of time, it is not easy to determine the chronological order of the discovery of pool salt and sea salt.
Well salt: well salt may appear a little later, according to the literature of the earliest in the Warring States period in the Ba Shu area.
Huayang Guo Zhi says that Li Bing, who knew astronomy, geography and water veins, invented the technique of digging salt wells.
Li Bing surveyed the distribution of underground salt brine and drilled salt wells while treating water.
Chengdu and other places have unearthed a number of salt wells portrait bricks, image reproduced the ancient well salt production.