hello, has anyone got an idea where i can buy this yam vegetable in chiang mai?

Makro has them, also I am sure you will find them in Muang Mai 

wholesale market near American embassy. 

 

regards worgeordie

I don’t know if you want a real yam or simply want sweet potatoes.

 

The later are available here at the markets but also at Rimping. In Rimping they have them both imported from Japan (expensive) and Vietnam (cheaper).

 

I find the ones in Rimping sweater than what they sell at the markets, presumably the ones at the markets are locally grown.

In the english language the word 'yam' has no precise meaning.  Depending on location yam may mean any one of several, swollen underground storage organs of tropical plants.  Define what you want then look at the local markets for that 'yam'.

Look here 

https://en.wikipedia.org/wiki/Yam_(vegetable)

They have really nice ones at Rimping 79 Baht each. Imported from Japan.