We use wheat free tamari (and not all tamari is wheat free so be careful).
When I go to a sushi joint without wheat free tamari I order Sriracha and mix it with the wasabi. You haven't had fresh sashimi until you've slathered it with that mix!
Went to a place once that had mixed the wasabi with the Sriracha in the plastic squeeze bottle ~ "they knew"!!!!!
Gonna try that!
POW!!!