From NetEase:

Chengdu police publish 17 codes/symbols used by thieves and burglars

Summary: Recently, Chengdu police made public 17 types of “casing markers/symbols”. “×” represents “plan operation”, ◇ represents “no one lives here”, a wavy line represents “beware of fierce dog”, while a rectangle with slashes represents “already thieved”. Police remind city residents to be on the lookout for secret symbols/signals made by thieves and to immediately report them to the police as well as remove them upon discovery.

[Translation of the above Chinese:]

Plan operation

4-5 units that can be thieved

Very wealthy

Dangerous, avoid

Beware of dog

Lots of police

Be careful of neighbors

Has alarm

Danger of being accidentally caught

No one on guard

No one lives here

Single female resident

1 child, 2 females, 1 male

Household has someone who works in a government department

Nothing valuable worth stealing

Not necessary to enter

Already thieved

Comments from NetEase:

明天到操场操到天明 [网易浙江省杭州市网友]:

I bet that pile of coins drawing often appears in front of the homes of LD. I suggest thieves add a drawing of a helmet behind those coins to represent that it is safe, because LD won’t dare to report their homes being burglarized, so it is extremely safe.

赎罪的一休佛 [网易山东省济南市网友]:

You don’t need to be afraid of thieves, what is to be feared is being robbed “legally”.

网易广东省深圳市网友:

Anyone who wants to steal from me better not carry money on them. I’m far poorer than thieves and if they let me catch them, I’ll clean them out.

网易江苏省手机网友:

Everyone might as well draw a “already thieved” symbol on their door, to protect against thieves!

rwvtkk0 [网易浙江省温州市网友]:

These coded symbols are far less frightening than the ice cold word “demolish“, because you can still do your best to protect against these, but that ice cold “demolish” cannot be protected against by the people.

liyt67 [网易山东省济宁市网友]：

Are Sichuan’s burglar codes used universally throughout the country???

ueriowq [网易黑龙江省大庆市网友]:

May the police please publish their revised secret signals and codes, this I bet is already no longer used.

网易广东省东莞市网友 [baggioxiao]:

A household with someone who works in a government department actually has its own special symbol. How is this kind of household treated?

jszzx [网易江苏省网友]:

This kind of so-called “making public” is truly black humor. The moment you “make public”, what thief would still be so stupid as to continue using these already “made public” coded symbols? He would immediately change them! — Chengdu police think they are so smart, treating the ordinary common people like little children? Treating thieves as dummies?

网易浙江省嘉兴市网友:

I don’t care what kind of thief you are, you’re dead if I catch you, or at least half-dead! That or you kill me first.

Have you ever seen these coded signals or symbols? Has your home ever been burglarized? Have you ever caught a thief?