Important by reading the legend and date on a coin is first of all to try to reconstruct the legend.
The standard couplet on the coins of Shah Jahan is:
shihab al-din muhammad sahib qiran sani
shah jahan badshah ghazi.
Once you look at the coin the couplet arrangement (reading from bottom to top) is:
ghazi
shah jahan badshah
sahib (sanah 1) qiran sani
muhammad
shihab al-din
Any word/symbol/digit which doesn't fit in it requires therefore extra attention.