Buddhism is still fairly new in modern North America and Europe.
As such, it's also misunderstood and misrepresented in the media.
For one thing, people have come to associate Budai with Buddha.
What's the difference? Well, Budai was a fat Chinese monk
Who it's said travelled the countryside with a sack (like Santa Claus).
In other words, he wasn't Siddhartha Gautama, the historic Buddha.
The confusion that gives rise to this misconception is simple:
Like Christ, which is an honorary title meaning "Anointed One"
Buddha means "Awakened One" and this title has been given to many monks.
Some believe Budai (Hotei in Japanese) was an incarnation of Maitreya.
It doesn't matter though, since Siddhartha Shakyamuni preceded him.
So those who rub Budai's belly for good luck are really only indulging naive superstition!
Images (from top to bottom-right): Laughing Budai Maitreya - circa 10th Century CE, Gandharan Buddha - circa 1st Century CE & Emaciated Buddha (Sikri Stupa) - circa 1st Century BCE.
Further Reading: Past Issues of Mythic May