[Retric]

These are hardly the first researches to want to correlate Japan’s dates with the Gregorian calendar. If you think the historic record is so wrong then feel free to do some original research and prove it, but don’t assume people are idiots.

Anyway, you have clearly already decided the issue in your own mind and are looking to justify it. So, no I am not going to waste my time providing evidence you can look up if you’re willing to consider the possibility you’re wrong then dare to do it yourself.

[prometheus76]

I feel the exact same way. They didn't share their methodology, and their claims hinge on the methodology they used for converting the dates. I'm not accusing them of anything. I'm asking to see their methodology. You are the one who is giving them the benefit of the doubt and assuming they did it correctly, which is antithetical to peer-reviewed science.

[Retric]

They didn’t need to do the correlation, other people have already done the leg work.

You’re effectively complaining they didn’t show their work when using dates from the Roman etc calendar. Historians really care about getting dates correct and have done extensive work to line up each historical calendar where possible.