When you think of Shankar and Jaikishan, we think of how similar or dissimilar they are in their personalities. Shankar was named after Lord Siva and Jaikishan after Krishna. True to their names, like Siva, Shankar was the haughty one of the two. Jaikishan was the cool and jovial one like Krishna. We may compare Shankar, to the sun, and Jaikishan, to the moon. While Shankar was a serious person, focused entirely on his work, Jai was a jolly go lucky guy who balanced his work with play. But, the two have some common traits as well like total dedication to their profession, care, generosity and sentiments. They perfectly complimented each other with their unity in diversity. Therefore, I always choose to refer to them as Shankar Jaikishan, without the hyphen since they are both the one and same to me.
