A field F satisfies n-linkage on a subset of Ḟ if whenever the quaternion algebras

are equal in Br(F) there exist z ∈ Ḟ with

for i = 1, 2, . . ., n. This linkage of quaternion algebras is examined and its relationship to the torsion freeness of I2(F) and to the strong approximation property is investigated.