72 hour transit visa eligible?

Yes, your itinerary is eligible for 144 hour visa free transit without any doubt, but please, be certain that your flight from Beijing to Tokyo does not have any kind of landing within South Korea.

Jacqueline, you are informed that it is not 72, but 144 hour visa free transit in Beijing area because 72 hours were replaced with 144 hours there, years ago.

Also, please, use correct terminology because it is not transit visa, but visa free transit, so there is no visa of any kind.

Hello Borut, Thank you kindly for your response! And for your advice on the correct wording regarding Visa Free Transit. I'm assuming that an eligible transfer would also be:
US > Hong Kong > connect to PEK thurs 10/19, apply for the 144 hr visa free transit, stay in Beijing until fri 10/20 & fly onto Tokyo/Haneda.
Thank you!!

Yes, It is very important to be very precise because only the immediate points before and after your mainland Chinese destination matter. So, in your case, we are talking about Hong Kong and Tokyo or in other words:

Hong Kong - Beijing - Tokyo

Everything before and after the segment I have mentioned, is irrelevant. By the way, this itinerary is definitely eligible.