Those of us that learn Mandarin according to the Beijing standard typically learn the expression 二百五 pretty early. While it seems to be the innocent number “250,” it actually has a slang meaning: “stupid” or “idiot.”
Those of us spending time in China’s south eventually come to a realization: you don’t hear 二百五 that much around here. What you do hear, especially in Shanghai, is 十三点 (“13 o’clock”). While it means basically the same thing as the north’s 二百五, it’s milder, often approaching something more like “silly” or “dopey” (in Chinese, 傻得可爱, or “cutely silly”).
Interestingly, Baidu Zhidao even gives us a poster child for the 十三点 look: a character once played by actress Zhao Wei (赵薇).
Baidu tells us that when it’s used between two people of the opposite sex, it’s often used in flirting (and most often comes out of the girl’s mouth).
As for origins of the expression, Baidu Zhidao gives us two main theories:
1. It’s a reference to an illegal move in a gambling game (6 and 7 can’t be played at the same time, and they add up to 13)
2. It’s a reference to an hour that traditional clocks do not strike (no military time back then!)
I thought 十三点 might be a fun thing to put on a shirt (more fun than “250” anyway), so I made this new one. I think it’s the kind of thing that laowai would enjoy wearing to see what kind of reaction it gets out of the Chinese, whereas the Chinese can’t fathom why a foreigner would possibly want to wear a shirt with that on it. (Good times all around!)
The Sinosplice shop has other conversation-starting Chinese-themed t-shirts.