Yamaimo (dioscorea japonica) or Nagaimo (dioscorea polystachya) is used in many places in Japanese cuisine — be it topping for Zaru-Soba together with Negi, or the ubiquitous Okonomiyaki.
Where I live, both are unobtainable, be it powdered, canned or fresh. So I have to look for an alternative. As many genuine Yamaimo/Nagaimo powders are expensive, I looked for alternatives.
It seems only “Wild Yam”, dioscorea villosa, is available as powders. Origins seem to be Mexico, Ghana or Indonesia, most of the times.
The interesting question is: Are cooking properties, especially the “slimey” and viscous texture, similar enough to Yamaimo/Nagaimo, that it can be used as a emergency-substitute?