I have a large picture book of cat breeds. They show a Korat, and the Russian Blue, and there are differences. One of the things to watch for in the Korat is that their coat "breaks" over their spine. That is, it is a bit ruffled whenever the cat sits. The Russian Blue is a more delicatly built cat having longer slender legs and a tail that is nearly as long as the remainder of the cat's body, although their coat is similiar to the Korat. The obvious difference is in he shape of their head. The Russian Blue appears to be part "Abyssinian". That their eyes should be decisively green in color, also that their coat is very soft and thick. A Russian Blue's coat should have the unmistakeable silver tipping which is sometimes more pronounced than the Korat's.
There is 3rd breed if blue cat, called a Chartreux. It is a typical British-appearing cat, with the "Winston Chruchill" look. The eyes on this cat should be yellow.
.......wayne
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