  In this paper we study the identification of boosted hadronically decaying
top quarks using jet substructure in the center-of-mass frame of the jet. We
demonstrate that the method can greatly reduce the QCD jet background while
maintaining high identification efficiency of the boosted top quark even in a
very high pileup condition. Applications to searches for heavy resonances that
decay to a $t\bar{t}$ final state are also discussed.
