I have used Nishiki, but I have no idea as to whether it is old or new.
I have seen rice grains from various suppliers that were smooth and
shiny and others that appeared chipped and broken. I suppose that
based on what you stated, chipped and broken is not the same as "small
cracks not readily visible."

How can I determine what is old and what is new? If you have any
specific suggestions (names of old and new rice and US suppliers) I
will try experimenting with them.

BTW, using more or less water in my Zojirushi seems to affect the rice
texture. Do you tend to use the exact amount of water recommended?

Also, do you wash and/or soak the rice before cooking? I know that
some people insist on washing and some also add a 45 minute soak in the
cooking water before cooking.

Thanks.