Importing a large truck - Emissions?

Hello all,

TLDR: Looking for emissions requirements for imports from the US. Bringing a Ford F250 or 350 and a large trailer to Japan, permanently. Drivers license is already done. Parking is not yet a concern. Currently still in the home searching process, but looking in rural areas, especially Iwate and Hyogo (personal reasons, very long story). Don't worry, the rig won't be driving through Tokyo, thank the gods.

Does anyone have experience with anything like this? I'm mainly concerned with the truck. I've seen plenty of people importing Ford F150's around model year 2000, but haven't seen anything bigger, older, or newer. I can't find the exact emissions requirements anywhere - still learning to Google in Japanese. Does anyone have experience on this or a link to where I can find specific emissions requirements? I'll be coming from California so I'm used to strict emissions laws, but I understand Japan will likely be more extreme. Everything I find online is just the importing process and people wanting to bring their muscle cars.

Everyone I see either imports or converts an old tour bus for the purpose I need, but if anyone knows of a place selling large trucks/towing vehicles in Japan, I'd be open to that as well. I really do not want to have to buy or drive a bus, I'm more comfortable with trucks and trailers. Thanks in advance for any help you can offer.

Wouldn’t a truck bought in Japan be more convenient? If you import it from the US, the steering wheel will be in the wrong side. I could imagine that for a truck that lack of visibility is a big challenge.

I am sure you would like to live out in a farm or such in the country and thats why you need a truck and trailer.

Most of the rural roads barely fit a small japanese made pick up and two definitely cannot pass side by side. A F150 would have a terrible time navigating rural roads and an F350 would have a terrible time.

Before bringing in the truck, see where you will like to live and the road situation around it.

An F250 is hardly large - I see similar vehicles driving around here in Tokyo. Sometimes they look out of place on the small streets or impractical, but people still buy them. And left or right hand drive doesn't seem to be an issue (I assume the documentation/licensing takes care of that).
One issue that might catch you, and this might be related to your emissions question - when it arrives in the country you will need to get it registered/certified. If it fails certification, you'll be stuck with a vehicle you can't drive.
BTW, emissions levels are given in the wiki for "shaken" (車検):
https://en.wikipedia.org/wiki/Motor-vehicle_inspection_(Japan)