A totally domestic itinerary... but if there are delays, connection is cooked.
Yes, this is Japan, so delays will be rare (and not taken well by both nationals and foreigners alike), and yes it is protected.
Reminds me of old days QF regional connections, e.g. at ports like MKY, CFS etc., which used to be able to be sold with MCTs of 20 or 25 min (instead of 40 min at larger domestic ports). Of course, if the weather has something to say, those rather unique, tight itineraries can be torpedoed.