This paper reviews research progresses of application of the conditional nonlinear optimal perturbation (CNOP) method in targeted observation of the Kuroshio in recent years,focusing on the Kuroshio path variations in south of Japan,the Kuroshio extension state transition,and the upstream Kuroshio transport variation.By calculating the CNOPs of the above cases,the localization features of the CNOP spatial structures are found for each event,which could be used for identifying the sensitive areas of the targeted observation.Results of ideal hindcasting experiments show that if the targeted observing strategies in the sensitive areas identified by the CNOP method are applied,the forecast skill of above events could be improved significantly.