  It has been shown that inter-spin interaction strengths in a spins-1/2 chain
can be evaluated by accessing one of the edge spins only. We demonstrate this
experimentally for the simplest case, a three-spin chain, with nuclear magnetic
resonance (NMR) technique. The three spins in the chain interact through
nearest-neighbor Ising interactions under site-dependent transverse fields. The
employed molecule is an alanine containing three $^{13}$C nuclei, each of which
has spin-1/2.
