These coins are from the Qing Dynasty which means they were minted between 1644 and 1911. The Manchu ruled China during this, the last, dynasty. So, one side of the coin is in Manchu and one side is in Chinese characters.

You find these coins on tables, on carts and in shops where tourists frequent. They are with the scarves, the cricket cages, the jade, the little red books of Mao's Quotations, the T-shirts, the combs, and anything else a tourist might, or might not, want. You even find them on the Internet.

I've heard different reasons for the square hole. I read the coins were made on a square rod which allowed many coins to be made at once and allowed the rough edges of the coins to be smoothed before the rods were removed.
Some people say ten or twenty coins were tied together on a string. You could then easily purchase items for the string amount. Others say, since clothing didn't have pockets, the hole was there so coins could be strung together and carried on your wrist.

The round outer edge and the square hole came to represent the sky and the four corners of the earth. Or mobility and stability, flexibility and strength. I was once told by a university student that the round edge reminds us we must be round on the outside so we do not clash in our dealings with people. But, we must be like the square on the inside so we don't forget who we are and the values we hold.
I liked that.

And here is something else I liked....a Zen proverb my brother Randy sent me. It gave us both a good chuckle.

Do not seek the truth, only cease to cherish your opinions.
If you understand, things are just as they are.
If you do not understand, things are just as they are.