Abstract:We study chaotic motions of a classical string in a near Penrose limit of AdS 5 × T 1,1 . It is known that chaotic solutions appear on R×T 1,1 , depending on initial conditions. It may be interesting to ask whether the chaos persists even in Penrose limits or not. In this paper, we show that sub-leading corrections in a Penrose limit provide an unstable separatrix, so that chaotic motions are generated as a consequence of collapsed KolmogorovArnold-Moser (KAM) tori. Our analysis is based on deriving a reduced system composed of two degrees of freedom by supposing a winding string ansatz. Then, we provide support for the existence of chaos by computing Poincaré sections. In comparison to the AdS 5 ×T 1,1 case, we argue that no chaos lives in a near Penrose limit of AdS 5 ×S 5 , as expected from the classical integrability of the parent system.