Oriental Shorthair — Color Genetics & EMS Calculator

The Oriental Shorthair is the most genetically unrestricted of the Siamese-family breeds, accepting virtually every color and pattern combination expressible in the 11-locus feline genetics matrix, including all B-locus alleles, the full Inhibitor (I) locus silver and smoke series, all tabby patterns, and all O-locus tortie combinations — but critically, without the colourpoint restriction that defines SIA. EMS codes for OSH span non-agouti solids, all four tabby patterns, bicolors, and pointed variants (Colourpoint Orientals, formerly registered separately), making a comprehensive EMS color calculator essential for managing the enormous combinatorial space. Feline genetics programs for OSH benefit from systematic locus-by-locus carrier analysis given the simultaneous segregation of B, bl, b, d, O, I, cs, and S alleles within the population.

Oriental Shorthair colour genetics: frequently asked questions

Which recessive colours do Oriental Shorthair cats commonly carry?
All color-locus recessives are present in OSH populations: chocolate (b), cinnamon (bl), dilution (d), and colourpoint (cs). The O locus produces red, cream, tortie, and torbie variants. Inhibitor (I) locus produces silver, smoke, shaded, and tipped phenotypes in all base colors. Oriental Colourpoints (cs/cs) are accepted within the OSH register in FIFe.
What colour restrictions apply to the Oriental Shorthair breed standard?
No significant color restrictions apply to the Oriental Shorthair under FIFe standard. Dominant White (W) is accepted. Amber (e) is not listed for OSH in FIFe standard. All tabby patterns are accepted. The colourpoint (cs/cs) Oriental is included in the OSH register. Bicolors are accepted, though white-spotted (S locus) Orientals are less common in the show ring.
Which coat patterns are typical for the Oriental Shorthair?
All four tabby patterns (22, 23, 24, 25) are accepted. Ticked tabby (25) is common and breed-typical in the OSH. The 'Foreign White' is a separate FIFe registration (OFW) for white Orientals — W/- cats — and is not coded as OSH in EMS. Silver tabbies, smokes, and shaded phenotypes are all common in OSH show lines.

Popular EMS Colors

OSH nBlack (solid)
OSH b 25Chocolate Ticked Tabby
OSH ns 24Black Silver Spotted Tabby
OSH a 33Blue Colourpoint (Oriental Colourpoint)
OSH fBlack Tortie (solid)
OSH c 22Lilac Classic Tabby

Calculate Colors for Oriental Shorthair

Free online cat color genetics calculator. Select the breed and appearance of the sire and dam to predict kitten coat colors, patterns and probabilities based on feline color genetics.

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Enter the appearance of both parents to calculate color predictions.

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