It would appear that Nazi Germany, represented by the swastika, is perceived as the greatest Axis threat. I can't say for certain, but the chain may indicate the control that Germany has over its allies. The obvious symbolism is of the enemy being venomous cobras which have to be crushed. One cobra has the Rising Sun Flag of the Japanese military. The other one has the fasces, a symbol of Italian fascism. It's an ancient image, originating from Etruscan civilization, of a bundle rods surrounding an axe, which represents power.