Abstract: We investigate the operator in the plane with an attractive singular interaction supported by a loop, and show that in the strong-coupling limit the negative eigenvalues converge to those of the Schroedinger operator on the loop with the usual curvature-induced potential. We also derive an estimate on the number of eigenvalues which has the correct semiclassical behaviour. For more details see P. Exner and K. Yoshitomi, math-ph/0103029.