The four soldiers must be paired together and cannot be separated; When Cao Cao, Guan Yu and the general move, there must be two small soldiers in front to clear the way; When Cao Cao moved, there should be two small soldiers chasing behind him; In the above three cases, each block can move locally at will (without interfering with other places).

Huarong Road game belongs to the slider game, which is to move something called "block" within a certain range according to certain conditions and finally meet certain requirements. The origin of the slider game can be said to be the "Nine Palace Rearrangement" in ancient China.

It should have been produced in the era when the book of Hutuluo appeared, with a history of thousands of years. 1865, the game of "Rescheduling Fifteen" appeared in the west, especially the game of "14- 15" introduced by Sam Lloyd in 1878, which was very popular.

Related History: Huarong Road was invented by China, and the final solution was worked out by Americans with computers. However, the design principle of Huarong Road is not clear. At first, it was a chessboard composed of twenty squares, a set of four small squares (Cao Cao), five sets of two small squares (five tigers and generals) and four sets of small squares (four soldiers).

But Guan Yu is two small squares horizontally, and the other four will be two small squares vertically, so if Cao Cao is four, the four generals and Guan Yu cannot be collectively called two, and the relationship of 1 * 2 * 4: 20 cannot be established.

Another way is to regard Cao Cao as the fourth power, Guan Yu as the square, four generals as four 2s, four soldiers as four 1, and the chessboard as 20. But the final mathematical principle has not been solved.