There are a couple different Irish coins with john's name. As king, he issued a full penny, half penny, and farthing (not cut pennies like in England...), and before he was king, Henry II made him lord of Ireland, and there are a few pennies of him as lord of Ireland with a different design.
Evan is going to be 5 in October. He wants to do a video of him talking about his coins - I am going to encourage him to post it here.
Quite an awesome coin! Psss. Vcoins has one and its nicer than mine. Its a little steep but IMHO well worth the ask.
That's always been my problem... they're a little steep. There's a half-penny on v-coins I've been looking at. Might nab it (b-day's coming up, that's a good excuse, right?)