Thank you for your replies.
Yoon, I hadn't thought about that, dragons are indeed associated with brining rain, so that could well be the link to the ears of rice on the ura.
Dale and Jake, thanks for the links to the similar style tsuba. On these tsuba the designs are more classic and matched on the omote and ura; Tiger and bamboo grove or Shishi lion and peonys flowers. I have not seen a dragon paired with ears of rice before on a tsuba. Or as Yoon has pointed out, perhaps the link between the two sides is that the dragon brings the rain for a good rice crop.
Keen to see any other examples of this design paired togehter or of tsuba with un-matched designs on the omote and ura.
Cheers,
Tom