To evaluate \( 6^{-1} \), we need to recall that a negative exponent indicates the reciprocal of the base raised to the corresponding positive exponent. Specifically:
\[ a^{-n} = \frac{1}{a^n} \]
So for \( 6^{-1} \):
\[ 6^{-1} = \frac{1}{6^1} = \frac{1}{6} \]
Thus, the answer is:
\[ \frac{1}{6} \]