I have not heard of this particular name but it sounds like the Kishu Mandarin. These are somewhat cold hardy. You might want to contact Stan at worldwideplants.com to see if he coould give you any information. He has a lot of very cold hardy citrus trees.

I wouldn't believe a word of what OE claimed in their catalog. They would say anything to get you to buy whatever. Hardy to zero is quite an exaggeration for any citrus. Citrus are hardy for a few hours of freezing weather. 24 hours of freezing weather will kill citrus trees. Survival outside for any edible citrus in anywhere colder than zone 8 is very unlikely to impossible unless you grow in a greenhouse.

Here is a link that might be useful: mrtexas

Oregon Exotics made up their own names, so you won't find it called that anywhere else.
'mrtexas' is right, truly hardy to zero Fahrenheit is impossible except for Poncirus and perhaps some of its hybrids.

I currently have a "Snow Picked Mini-mandarin" that came from Oregon Exotics years ago. This is the first year to bear fruit, and it is loaded. It is definitely NOT Kishu mandarin since it does have seeds. It is also not sweet, but that might be due to my picking one too early for proper tasting. These are in the process of turning color. Very few of them are any wider than 3/4 of an inch, and less in height. Six sections with a seed in each section. Peels rather easily.