Hongmei squatted on the edge of the kiln, and she smeared a layer of strange things on the small clay bowls that had not yet been fired, including table salt, wild vegetable juice, lard, fish oil, and even a little relief from her morning wake.

She wanted to burn pottery with a smooth surface.

So far, Hongmei's attempts have failed.

But Gu Guo has a more important task to his aunt.

Although the primitive tribes of the Neolithic were poor, they also bartered, but the success rate of bartering was very low until the general equivalent came out.

For example, Zhang San wanted to find Li Si to exchange meat for a stone axe, but Li Si didn't need meat, and the result was that the business could not be negotiated, and the exchange of items was very inefficient.

That's when the concept of money comes in.

In ancient times, people used rare metals such as gold and silver as currency, and the rarity, portability and durability of gold and silver determined that money was naturally gold and silver, but the Great Teacher also said that gold and silver are not naturally money.

The ancient people along the coast used beautiful shells as currency, and the people of the interior used all kinds of bronze metal as the general equivalent of the goods of trade.

But Gu Guo had neither shells nor copper or tin mines, but he had one thing in his hands - pottery.

Within a radius of thousands of miles, pottery is the most advanced product among the primitive tribes, and it will take at least a while for other tribes to imitate it, so Gu Guo is not worried that there will be fake pottery coins in circulation, anyway, when the time comes, it will be fully replaced with copper coins, and the pottery coins are completely enough to be used as a transitional product.

The currency standard of the pottery coin is all kinds of clay pots, pottery bowls, pottery pots and other objects piled up in the cave, the pottery demand of the tribe where the Gu country is located has been saturated, and the pottery coin is a pity for the people to eat tastelessly, and its value is not even comparable to a pottery bowl for drinking soup.

But for other tribes, once this thing enters the market, it will be a dimensionality reduction blow.

The pottery coin exports the surplus pottery to various tribes, and then uses the scissors to harvest the productivity of each tribe frantically, just like a superpower in Gu Guo's previous life frantically harvested the whole world.

Gu Guo will not fish with all his might, catch a wave and run, his vision is very long-term, in the future, these surrounding tribes will sooner or later merge with his own tribe, and gradually develop into civilization, common prosperity is his heart's desire.

Sooner or later, the increasing number of pottery will saturate the market, and the pottery coins that use pottery as the currency standard will plummet, perhaps one pottery coin for five clay pots this year, and two next year.

Gu Guo shrugged, thinking about it later, let's circulate the pottery coins first, this step is difficult, it is completely using the reputation of the tribe as a guarantee, so he decided to send some pottery coins to each tribe first, so that they can exchange pottery and food, and after tasting the sweetness, they may be able to accept this general equivalent.

He tied two branches together with a fiber rope, and the two ends were sharpened to act as a simple compass. Cut a palm-sized circle on the mud cake with a compass, draw a circle about one-half from the center of the circle, representing the big earth under your feet, and then hollow out with a compass in the middle, implying the sun in the sky, and draw a circle line with the radius of the center of the circle between the sun and the big earth, implying the orbit of the big earth around the sun.

On the back, four five-pointed stars are carved in four directions, up, down, left and right.

It took Gu Guo half an hour to finish this piece of pottery coin, which was more time-consuming than pinching a clay pot with a potter's wheel.

Teach the details of the production to her aunt Hongmei, who turned over the fired pottery coin in her hand and turned it over, never thinking of the use of this palm-sized pottery shard.

There is no distinction between face values of pottery coins, and Neolithic people could not calculate too complicated addition, subtraction, multiplication and division, as long as they simply set a standard.

Of course, this standard was formulated by Gu Guo, who has mastered the advanced productive forces.

How much food and salt can be exchanged for a pottery coin, how many pottery pots, a few pottery bowls, and a few pottery pots, these things, when the pottery coin is issued, Gu Guo can be completely condemned to death, and then regulated by the market.

Some items that Gu Guo could not quantify, such as bone polished ornaments, stone axes, stone spears, etc., could only be negotiated among the tribes, but Gu Guo, who had the power to price grain and salt, was optimistic about the pricing of these items.

There are three days left for the gathering of the tribes, and these days the tribes are hunting with all their might, burning pottery, and making salt.

All kinds of bacon, cured meat and salted fish in the cave are piled up, Gu Guo estimated that he had to have two thousand catties, for a tribe of only more than seventy people, it would not be a problem to eat for a month without leaving home, but the taste of salted fish was a little rushed when he slept at night.

As for the salt, it was filled with more than a dozen clay pots, and at this stage, this thing was about equal to strategic materials, and Gu Guo was ready to take out only two cans in exchange.

What worries Gu Guo the most is that the pottery in the innermost part of the cave has been piled up, and his aunt Hongmei seems to be addicted to pottery burning, squatting on the edge of the kiln all day long, and now the clay pots in the cave are close to three hundred, and the places where the people sleep are almost not enough.

It seems that because the pottery coins have not yet been circulated, the contribution points of the system reward have not come.

"Alas, we have to build a house, and it's not a way to live in a cave all the time."

Gu Guo sighed and glanced at the various animal skins that were neatly stacked together. Equipped with bows and arrows, the production of hides increased day by day, allowing the people to spend the winter outside the cave in fur coats.

He hoped to find a copper mine before the onset of winter, and then refine copper tools so that he could carve out a settlement on the plains, and then find crops to cultivate in the spring.

Before the birth of polyploid crops without artificial breeding, ancestors such as wheat and rice grew almost indistinguishable from barnyard grass, and the ancestors of watermelons were almost all melon skins...... Moreover, Gu Guo didn't know that there were some edible plants on his planet, and it was even more difficult to develop farming.

Simple botanical knowledge!

Thinking of the price of up to 1,000 contribution points, Gu Guo's whole body wilted.

Every time the technology on the technology tree is lit, it is inextricably linked with the progress of productivity and the accumulation of time, which is interlocking but complementary to each other.

Gu Guo scratched his hair in distress and touched the oil on his hand. It seems that I haven't washed my hair for many days.

"By the way, plant ash, animal oil, you can make soap!"

Now Gu Guo's hair is like a reflective straw, dandruff is lying on the root of the hair in large chunks, and the hand that has touched the hair is crispy, which is the sebum secreted by the scalp.

But now it was too late to make soap, and it would take two days to get to the place where the tribe would meet, and the priest decided to set off tomorrow morning, and Gu Guo could only boil large pieces of fat into oil and dissolve the ashes of the plants and trees in a clay pot.

It takes a long time to dissolve the plant ash, the upper solution is filtered several times to obtain a relatively pure lye, and then the lye and the oil are mixed and heated and stirred to carry out a full saponification reaction, and finally the reaction solution is poured into the mold and let stand for a period of time, after it is completely solidified, a large piece of complete soap is made.

Gu Guo burned it for a day, burned out more than 20 catties of grease, and the jar containing the plant ash solution was sealed by him with animal skins to prevent the clansmen from being corroded by lye. After doing all this, get into the skin sleeping bag and wait for the next day's team to leave.