What Colour Will My Litter Be?

Most breeders want the answer to this question. To get a full answer you need to know the colour of the Stud and the Queen, you also need to know the colours they both carry - i.e not just the colour you can see but the "hidden" colour/s they may have inherited from their parents.
When you DNA test your breeding cat for its coat-pattern and to rule out problems such as required by the Tonkinese Registration Policy, you can also test for colour - this will give you an accurate picture of your cat and you should expect that the owner of the cat being mated with yours will have the same information.

Once you have this information you can go through the process of creating a Punnett Square (a device geneticists use to calculate inheritance), listing all the variations for each possible combination and then you can work out what the litter may be. Such as the one on the right that might be used for Brown Tabbies.

... or, you could use a handy book that has been written to calculate all the combinations for your particular queen.
... or, for a quick check of the basic colours (brown, blue, chocolate, lilac, red and cream) you could use an on-line calculator! 
... both of which may be found on Linda Vousden's Tonkinese web site.