Non-Perturbative Determination of $c_{\rm SW}$ in Three-flavor Dynamical   QCD
  We present a fully non-perturbative determination of the $O(a)$ improvement coefficient $c_{\rm SW}$ in three-flavor dynamical QCD for the RG improved as well as the plaquette gauge actions, using the Schr\"odinger functional scheme. Results are compared with one-loop estimates at weak gauge coupling. 
CP-PACS and JLQCD Collaborations: S. Aoki, M. Fukugita, S. Hashimoto,   K-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T...