Not a Japanese person, but the way this has been explained to me feels slightly broader than the concept of vocation.
The explanation was more along the lines of, "what gives your life meaning, joy, and purpose, and makes you motivated to get out of bed every morning and venture out into the world to do your thing and contribute to the world around you".
So your vocation might be teaching more generally but your ikigai might be teaching that one class of delinquent kids nobody likes, and striving to make them succeed, for example? But maybe I'm wrong.
The explanation was more along the lines of, "what gives your life meaning, joy, and purpose, and makes you motivated to get out of bed every morning and venture out into the world to do your thing and contribute to the world around you".
So your vocation might be teaching more generally but your ikigai might be teaching that one class of delinquent kids nobody likes, and striving to make them succeed, for example? But maybe I'm wrong.
Also, the venn diagram at the bottom is lacking the most important information, what the 'curved triangles' represent. There's a better one here: https://i0.wp.com/marieskelton.com/wp-content/uploads/2020/0... (ironically taken from another article like the one linked here. https://marieskelton.com/finding-your-passion-and-purpose/ )