Ramen Bayashi in Narita red chili pepper soup

I have been trying to recreate the red chili pepper soup (shisenmen) since I retired as a flight attendant. Desperately miss it,but can't determine what style of ramen base this is. I know it has sesame paste in it but not much more. Anyone able to help?

I have no way of knowing what soup stock they use (whether it is pork, chicken, vegetable, etc.) but the flavoring seems to be considered very mild among the Japanese who tried it (this place seems to be known well among non-Japanese CA).

And the locals who ate it there said it looks like gmiso-basedh flavoring, (usually red chili soup would be red at a glance) with a bit of spices in it. gShisenmenh means gSichuan noodles,h so i was expecting to see some real red soup as i searched online, but the color suggest otherwise.

So maybe you could try looking for gmiso ramenh recipe first, then maybe try adding a bit of red chili or Chinese Doubanjiang paste?
Have fun!

Thank you so much for giving me your time. Will give it a try using a miso base and the sesame paste,

From the website it say sesame flavor spicy soup ramen, which is Japanese version of Sichuan dandan noodles.

have a look at this site for recipe and idea
https://thewoksoflife.com/tan-tan-ramen/