To provide a combination of an aqueous ink and a preservative liquid for inkjet printing to introduce the ink into an inkjet head easily.

This aqueous ink and the preservative liquid are selected so as to satisfy a relationship of equation (1), wherein when one end of a capillary tube with an inside diameter of 0.1-1 mm is dipped in the ink and the ink rises in the capillary tube, a rise speed of the ink at a middle point between before rise and after rise is represented by Vs, and when the capillary tube is wetted by the preservative liquid, a rise speed of the aqueous ink is represented by Vi.