diff --git a/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts b/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
index b6b650b..bd5c7ec 100644
--- a/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
+++ b/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
@@ -174,7 +174,7 @@ describe('Farbschlag catalog', () => {
 
   it('falls back to Unbekannter Farbschlag for uncatalogued genotypes', () => {
     // E-dominant (no Fuchs/Schimmel family) + an uncatalogued cchm/dd/gg/pp combo.
-    const match = farbschlagFor(fromDisplayString('aa cchmcchm dd EE gg pp spsp rere'))
+    const match = farbschlagFor(fromDisplayString('aa CC dd EE gg pp spsp rere'))
     expect(match.unknown).toBe(true)
     expect(match.name).toBe('Unbekannter Farbschlag')
   })
@@ -222,7 +222,7 @@ describe('Farbschlag catalog', () => {
   it('genotypeToFarbschlag (DATA-1 denormalization contract) returns the plain name', () => {
     expect(genotypeToFarbschlag(wildType())).toBe('Agouti')
     expect(genotypeToFarbschlag(fromDisplayString('aa CC DD EE GG pp spsp rere'))).toBe('Platin')
-    expect(genotypeToFarbschlag(fromDisplayString('aa cchmcchm dd EE gg pp spsp rere'))).toBe(
+    expect(genotypeToFarbschlag(fromDisplayString('aa CC dd EE gg pp spsp rere'))).toBe(
       'Unbekannter Farbschlag',
     )
   })
@@ -399,3 +399,33 @@ describe('GEN-3d: dominance tiebreak for unknown loci', () => {
     )
   })
 })
+
+describe('GEN-3e: C-locus colourpoint naming', () => {
+  const name = (s: string) => genotypeToFarbschlag(fromDisplayString(s))
+
+  it('A- + cchm/cchm -> CP-<base colour> (CP-Silberagouti example)', () => {
+    expect(name('AA cchmcchm DD EE gg PP spsp rere')).toBe('CP-Silberagouti')
+    expect(name('AA cchmcchm DD EE GG PP spsp rere')).toBe('CP-Agouti')
+  })
+
+  it('A- + cchm/ch -> CP-<base colour>', () => {
+    expect(name('AA cchmch DD EE GG PP spsp rere')).toBe('CP-Agouti')
+  })
+
+  it('aa fixed colourpoint names (Marder/Siam/Zobel/Zobel-Hell)', () => {
+    expect(name('aa cchmcchm DD EE GG PP spsp rere')).toBe('Marder')
+    expect(name('aa cchmch DD EE GG PP spsp rere')).toBe('Siam')
+    expect(name('aa cchmcchm DD EE gg PP spsp rere')).toBe('Zobel')
+    expect(name('aa cchmch DD EE gg PP spsp rere')).toBe('Zobel-Hell')
+  })
+
+  it('chch stays Hermelin (aa) / Himalaya (A-); full C => no CP', () => {
+    expect(name('aa chch DD EE GG PP spsp rere')).toBe('Hermelin')
+    expect(name('AA chch DD EE GG PP spsp rere')).toBe('Himalaya')
+    expect(name('AA CC DD EE GG PP spsp rere')).toBe('Agouti') // one full C -> no colourpoint
+  })
+
+  it('colourpoint composes with the Schecke modifier', () => {
+    expect(name('aa cchmcchm DD EE GG PP Spsp rere')).toBe('Marder Schecke')
+  })
+})
diff --git a/gerbil-manager-web/src/genetics/catalog.ts b/gerbil-manager-web/src/genetics/catalog.ts
index 0c2e468..a1e3c00 100644
--- a/gerbil-manager-web/src/genetics/catalog.ts
+++ b/gerbil-manager-web/src/genetics/catalog.ts
@@ -191,25 +191,61 @@ function eFamily(g: Genotype): string | null {
 }
 
 /** Resolve a genotype to its German Farbschlag (with Schecke/Rex modifiers). */
-export function farbschlagFor(g: Genotype): FarbschlagMatch {
+/** Resolve an allele pair to concrete alleles, defaulting unknown to wild-type. */
+function resolvedPair(g: Genotype, locus: LocusKey): [string, string] {
+  const alleles = LOCI[locus].alleles
+  const isMarker = locus === 'Sp' || locus === 'Re' || locus === 'Sls'
+  const fallback = isMarker ? alleles[alleles.length - 1] : alleles[0]
+  const [x, y] = g[locus].map((a) => (a === WILDCARD ? fallback : a))
+  return [x, y]
+}
+
+/** Base colour name (no modifiers, no colourpoint prefix), via E-family + matches. */
+function baseColourFor(g: Genotype): string | null {
   const family = eFamily(g)
-  // When the animal is a Fuchs/Schimmel-family genotype, only entries that
-  // explicitly pin the E locus may name it (so e.g. eef can't masquerade as a
-  // C-series white via wildcard C); otherwise fall back to the family name.
   const base = family
     ? (BASE_COLORS.find((e) => e.tokens.E !== undefined && matches(g, e)) ?? null)
     : (BASE_COLORS.find((e) => matches(g, e)) ?? null)
+  return base?.name ?? family
+}
 
+/**
+ * GEN-3e: the C-locus colourpoint NAMING transform (breeder-authoritative).
+ * Returns the colourpoint name, or null when it doesn't apply (full C present,
+ * or chch — which the base matcher names Hermelin/Himalaya, preserving both).
+ *   aa cchm/cchm        -> Marder      | aa cchm/ch        -> Siam
+ *   aa cchm/cchm gg     -> Zobel       | aa cchm/ch gg     -> Zobel-Hell
+ *   A- cchm/cchm | cchm/ch -> CP-<base colour> (base computed as if C were full)
+ */
+function colourpointName(g: Genotype): string | null {
+  const c = resolvedPair(g, 'C')
+  if (c.includes('C')) return null // a full C allele => full colour, no CP
+  if (c[0] === 'ch' && c[1] === 'ch') return null // chch -> base matcher (Hermelin/Himalaya)
+  // Remaining: cchm/cchm or cchm/ch (colourpoint, no full C, not chch).
+  const bothCchm = c[0] === 'cchm' && c[1] === 'cchm'
+  const agouti = resolvedPair(g, 'A').includes('A')
+  if (!agouti) {
+    const [g1, g2] = resolvedPair(g, 'G')
+    const grey = g1 === 'g' && g2 === 'g'
+    if (grey) return bothCchm ? 'Zobel' : 'Zobel-Hell'
+    return bothCchm ? 'Marder' : 'Siam'
+  }
+  // A- colourpoint -> CP-<base colour>, base as if C were full.
+  const base = baseColourFor(makeGenotype({ ...g, C: ['C', 'C'] }))
+  return base ? `CP-${base}` : null
+}
+
+export function farbschlagFor(g: Genotype): FarbschlagMatch {
   const modifiers: string[] = []
   if (locusToken(g, 'Sp') === 'Sp') modifiers.push('Schecke')
   if (locusToken(g, 'Re') === 'Re') modifiers.push('Rex')
 
-  const baseName = base?.name ?? family
+  const baseName = colourpointName(g) ?? baseColourFor(g)
   if (!baseName) {
     return { name: UNKNOWN_FARBSCHLAG, base: null, unknown: true }
   }
   const name = [baseName, ...modifiers].join(' ')
-  return { name, base, unknown: false }
+  return { name, base: null, unknown: false }
 }
 
 /**