There has not been a single honorific in this whole series. All characters refer to each other by their first name (except for Maki - but that's because people think Maki is her first name) without anything attached. Not sure if this is something that's common among outdoorsmen or if it's just an author preference thing. Though I do remember that out on the trails in Tokyo you would always say hello people as you passed each other by, which is very much so not a thing in the city.
