question about SEO technique

Hello,
while doing research in my niche I made some interesting disovery.

There is one major player in this niche which couldn't be reached on 1st place but 2nd place is owned by some guy probably running his website alone using some interesting SEO techniques.

For everyone with a little experience this of course might be nothing special and common business but for me as I just started it still is something new.

Whereas almost all other players in the niche use some common link mix (blog,forum,content-links) this guy has links from about 10 blogs which are blogs that been only created for the purpose of linking him means they have some minimal content but properly written usually 3-5 pages overall with a few thousand words including some of his keyword links.
The interesting thing is that those blogs first been establish and linked for a totally different topic even in a different language. One of the strongest blogs which shows a very strong link profile is related to fluorid in water in english, then been completly changed to german and rewritten in relations to the products of my competitor. The fluorid water topic the blog was originally about probably was only chosen as it was a popular topic back in the time with not so much competition means the only aim this blog was ever built was to connect it to some shop with a different topic afterwards.

Could somebody maybe point me in a direction to find further information about this technique.
It seems it is very powerful as this guy with about 10 blogs of this type easily keeps the number 2 position behind a multimillion dollar company with thousands of links.

Also if somebody could help with something like this/uses this technique himself feel free to contact and make an offer. Seems to me that of course it is quite some effort to establish such a blog but if there are only about a few of them necessary to noticably enhance ranking it might be worth to invest in this.

Thanks
Marc

really nobody here anything to say? If this is a unknown technique for those keeping silence, it might be worth to check.
If not and you think this is not a proper thing to do I would be interested in opinions, why.
Could be that the guy has some other strong links or onpage tricks going on I missed but as far as I can see the blogs are his best links and as mentioned he is on position 2 directly behind a multi million dollar company with several thousand high quality links.

He probably bought the blogs and repurposed them. That is not too special.

thanks. This comes with a big investment I guess as buying a whole blog which is properly linked is something else than selling spots for guest posts.
Since the whole topic and even language was changed isn't there any risk google detects this? I mean the only purpose of the blog when it was built was linking and the whole purpose after it was changed is linking to the shop which has nothing to do with the links the blogs initially got.
If this is a solid technique does somebody know where to buy such blogs? Again this are no blogs that are built up to bring value to readers but their only purpose seems to be to be linked in the best way possible and then sold.

That's called a PBN!! It's what blackhat seos have been doing for years. Search in google: pbn blackhatworld.

Sounds link a typical PBN but he made the mistake of not hiding them from 3rd party crawlers, hence you found them. It's quite possible there could be more that are hidden too.

ok, I did know about PBN but seems I had a wrong idea about how they work also I thought the times they are a powerfull/reliable tool are over.
Seems if done properly this is still not the case.
How could they be hidden from 3rd party crawlers if they are regularly linked? Aren't they also hidden from google in this case means have no effect on ranking then?
If this is still a common method can somebody maybe point me to some further information on how to built a proper PBN page without the risk of being detected and penalized?

Yes, like mentioned before, sounds like a typical PBN.

It's highly unlikely that you see the entire network though. What you probably see is just a small fraction of sites that have failed to bock backlinks checkers for some reason (maybe server misconfiguration etc.)

I think this is a good starting point for you: https://www.blackhatworld.com/seo/the-no-nonsense-guide-to-building-your-pbn-in-2017.944503/