To cope with the plethora of real life names for various white patterns, PKC invented its own range of names for set white patterns to make standard writing and reading easier, and UKC has adopted this. In addition, most colours will have a "strict" and a "relaxed" range. Some breeds require the strict rules to be followed, others allow the relaxed range. If no range is listed, assume that it is "relaxed". Note that in hairless breeds white is represented by pink. However so are a lot of other colours, so bear that in mind when judging the white spotting pattern on a hairless pet.

Species Similarities & Differences

Cats and dogs are very similar in how they display white. However there are notable differences which, if you are more familiar with one species than another, might trip you up. Generally speaking, colour (i.e. 'not-white' fur) flows down from the top of the pet, its spine and back of the head, down the sides, and last of all going under the belly and colouring the legs and feet - almost as if someone has thrown a bucket of paint over the animal. However the details of how white behaves on each species differ:

Dogs are fairly regular creatures, their white shows up fairly evenly, any breaks in patterns are usually minor and predictable. The white fur can be ticked or roaned, but patches where present tend to be of a reasonable size and fairly soft and rounded (Dalmatian spots aren't patches, they are a modified roan and harlequin Great Danes aren't white, they are a modified Merle). Dogs tend to have higher white socks on their forelegs than their hindlegs.

Cats are also fairly regular, but have a bit of a random factor and can throw some unusual patterns - moustaches (either white or coloured), split faces, almost complete bands of colour around a leg are not uncommon, and their patches can be large or small, rounded or irregular. However when their fur is white, it is never roaned or ticked. Unlike dogs, they actually tend to have higher white socks on their hindlegs than their forelegs. For a more detailed explanation of how white spotting in cats works, check out Messybeast's Bicolour page.

Sleeves

A sleeve is when an animal has an almost solid coloured leg in an otherwise higher degree white pattern such as piebald/harlequin.
The following guidelines exist on sleeves:

One sleeve "per animal" is allowed. Having two coloured sleeves on a high degree white animal is just too rare/unrealistic.
The toes/fingers must still be white on the leg with the sleeve.
The sleeve should be attached to a body patch of some sort.

Feline Patterns

In cats there are two types of white patterns: low white and mid-to-high white. The low white patterns have clear patterns that identify them, whereas the high white is a spectrum of patterns that flow from bicolour to van. There is some overlap between patterns (e.g. a high white Tuxedo may also pass as a Bicolour) but as long as the cat in question fits an allowed pattern for its breed, that is all that matters. Note, unlike dogs, cats are never roaned or ticked.

Note: The breed standard of each breed may have additional rules of where white must and must not occur - this doc here is just the basic definition, check standards before assuming these apply to your chosen breed.

White on Tails

As a default, cats with any degree of white on their tails are not accepted as A-reg. However, for all the white spotting patterns listed below, certain cat breeds may allow white tailtips. Consult the individual breed standards to see if this is allowed. If you believe and have evidence (such as images of irl champion cats) that a certain breed allows white tailtips, and white tailtips are not already accepted in that breed, please speak to the stewards so we can review adding them to the standards.

Low White

Mitted and Tuxedo reflect two quite specific patterns in cats, with very clear requirements and a characteristic appearance. Trim is more variable and flexible. Unless the standard of a breed says otherwise, mildly asymmetrical markings are equally acceptable as symmetrical. These patterns cannot have blue eyes unless also colourpoint or mink.

Pattern Name	Pattern Description
White Trim	One, several or all of the following white markings: - throat patch - chest patch - chin - jaw - toes - fingers - snout - jowls - blaze or locket (a locket is a small spot) between eyes and/or on forehead
Mitted	- Minimum: White toes/fingers on all four feet and white chin. - Maximum: White front feet up to and including the wrist, white hind feet up to and including the ankle. White chin with or without a spot and/or blaze on the muzzle and/or forehead. White front of chest and underside of body. Note - if the cat has more than minimum mitted markings, a white chest patch is required.
Tuxedo	- Minimum: White chest patch, white on most of the toes and fingers - Maximum: White muzzle and blaze, neck and chest (may include forelegs), underside of belly, feet and lower legs. For the white belly to be present, the cat needs a large chest patch (with or without a white collar). It is acceptable for one or a few of the toes/fingers to be coloured, but white must predominate. Unless classed as strict, any combination of white inbetween the minimum and maximum pattern is allowed.

Mid-to-High White

These three patterns represent a continuum of increasing white from Bicolour through Harlequin to Van. Unless the standard of a breed says otherwise, moderately asymmetrical markings are acceptable. These patterns may have one or two light blue eyes. See the Eye Colours doc for more information.
Note: The examples given for the head and body/legs are just that - examples. They do not represent the only way to pattern a cat, just examples of how cats range from mid-to-high white, and from more solid to more broken patterns. The ear and tail examples are less flexible but there are still some options with paintballs at the point where the white and coloured fur meet.

PATTERN	BICOLOUR	HARLEQUIN	VAN
Description	Up to 75% white, colour present on body and head as a blanket or patches. Lower legs and chest must be predominantly white, and the cat must have white on at least one of the following body parts - chin, throat or jowl(s).	More than 75% white, white placement as for Bicolour but with more white on the body +/- head.	Colour only present on head around at base of ears (may not be visible in pose) and tail, with optional coloured ears and up to 3 small body patches. White ears preferred.
Ears (see special notes below table)	- no white - white outside edge up to tip - white outside edge over tip - white tip	- no white - white outside edge up to tip - white outside edge over tip - white tip	- no white - white outside edge up to tip - white outside edge over tip - white tip - solid white**
Head	No specific minimum requirements but no white on the head would be very uncommon.	No specific minimum requirements but no white on the head would be very uncommon.	Colour restricted to around base of ears (ears themselves may be any accepted pattern as covered in the Ear section). Note that the last example does have colour behind it's ears, but it is not visible in pose - these cats MUST have colour on the ears if their head colour is invisible in pose - they cannot have solid white ears if no head colour is visible in pose.
Blue Eyes	Allowed in some breeds, see eye colours doc	Allowed	Allowed
Muzzle/Chin - small spots of colour on muzzle (e.g. moustache)	Allowed	Allowed	Not Allowed
Body & Legs		* *
Legs - Coloured Sleeves	Allowed but must be in balance with the overall amount of white on the cat	Not Allowed	Not Allowed
Legs - coloured toes and/or small spots on legs	Allowed	Allowed (but not more than 1-2 per cat)*	Not Allowed
Tail

KEY
* Not allowed if the breed standard specifies Strict Harlequin
** Only allowed if the cat has visible colour around the base of the ears in pose

Extra Notes on Ears

A PFM ear is shown in the examples. Hexed breeds may have different ear shapes, but fundamentally they have an outside edge, an inside edge and a tip. If the edges can be partly coloured they still fall within the definitions of 'up to but not over the tip' and 'over the tip'.
Paintballz can be applied to the ear tip ball to push the white right up to the tip and still fit within the 'up to but not over the tip' definition required for most Bicolours.
A cat may have different placement of white on each ear, as long as both are appropriate for the cat's overall white pattern.
White must only occur on the ears when it also occurs nearby. Although it does not need to visibly connect to the ear white in pose, white must be present on the collar or head nearby (muzzle/throat isn't nearby). It isn't realistic for a cat with a solid coloured head and neck to have white on the ears.
Although it can't be seen in shows or registrations, the back of the ear must reflect the level of white on the whole ear - if the rest of the ear is mostly white, the back of the ear should be white, and vice versa.
If an ear part can be seen, it must be the appropriate colour, BUT if it is obscured, it will be given the benefit of the doubt. What this means is that if part of the ear is obscured by fur in longhairs or by the shape of the ear in folded or curled ears, that part of the ear will be assumed to have an appropriate colour. If however any part of that section of the ear is visible it will be judged (e.g. if half the lateral edge is visible, it will be judged as per the guidelines for the lateral edge).
The following three ear patterns are unrealistic and are not allowed: