Chows aren’t dumb, they’re just misunderstood.
You have to remember that they were herded in droves across Asia and Eastern Europe by Genghis Khan’s mongol warriors as a food source, thus they are very wary of humans and don’t want to do what you say.
I trained my daughter’s chow by
1. never approaching him from behind and
2. by carrying a make-believe cast iron skillet in my hand while walking him. Every time he pulled on the leash, I pretend whopped him over the head with the pretend skillet, with pretend sound effects. In no time at all, he was walking like a gentleman and reliably sitting and staying. Like cats, I discovered, Chows are visual. They get mental images rather than verbal commands. Once you understand how to talk to them, they’re fine obedient dogs.
Thanks for the Chow training insight. Interesting.