A pair of the electrochemical oscillators was entrained with a short distance between the electrodes. A phase map of the entrainment was obtained as a function of the distance and their intrinsic frequency ratio. Each entrainment zone formed a triangle in shape as predicted by Arnold. Although each oscillation was periodic under decoupled condition, coupling out of the zones evolved aperiodic oscillations. Magnetizing one of the coupled iron electrodes induced pattern hopping among the zones. This magnetic field effect was ascribed to reduction of the oscillation frequency, which was drastically anisotropic depending on the magnetized direction to the reaction surface. (C) 2012 Elsevier B. V. All rights reserved.