Salt was so valuable in ancient China that the government monopolized its production and sale for over 2,000 years. The salt tax (盐税) was a major source of imperial revenue.
history
The simplified character 盐 comes from the traditional 鹽, which was extremely complex (24 strokes). It's one of the characters most dramatically simplified.
The vessel radical at the base indexes the character, picturing the dish or container in which salt was collected and stored. The radical preserves the original 鹽 / 監 semantic core — something gathered into and watched over in a vessel.
The 卜 mark on the upper left is a simplification residue from the traditional 鹽 (which had 鹵 'rock-salt vat' on top of 監 'inspect'). The 1956 reform reduced the heavy top to a small two-stroke marker plus an earth element.
The earth element next to 卜 carries a faint semantic flavour — salt as a mineral pulled from the ground. Together with the divination stroke it forms the simplified top half that replaces the older 鹵+臣 stack of the traditional character.
