Not a spinoff. It was founded 20 years before and was the largest PC manufacturer in China 10 years before buying IBM's PC business.

Interesting. Did not know that. I thought someone bought the IBM laptop business and renamed it.

It was bought, but after the renaming. Today IBM only build Servers. Mainframes. All other PC, Laptop and Server Production/Branding is sold. IBM rebranded mainly to IBM iX. A full service agency. Hardware is now Mainframes. And other deviations are mostly Cloud, OpenShift, Ansible, and RHEL.

They did, but they also were a large existing manufacturer.

I don't know what they had before but their identity seemed to be IBM's overnight (thinkpads and all).

They used the Think(Pad|Centre) brand and expanded it to other things (like IdeaPad).

They basically bought IBM's good reputation name and style and used it for both IBM-alikes and budget machines.

Some of it was good machines, some of it was crap.

They actually bought entire ThinkPad R&D as well, and have been subcontracted manufacturer for some time before that.

So Thinkpads are still designed in ex-IBM Lenovo Japan