Six meters long! Wow. You don't see 19 foot long planks these days.

What grading system are you employing? The wood is way better than #1 hardwood lumber in the common US grading system would be (#1 being about in the low middle of the scale).

White pine lumber uses a different grading system, which doesn't include a grade 1. Here's a good picture https://www.hancocklumber.com/land-mills/sawmills/pine-grades/

Different species actually each have their own grading system, defined usually by the trade group for that species, so southern yellow pine uses a different system than eastern white pine, for example.

Flooring may well have a whole different grading scale, which will probably also vary from country to country and perhaps species to species. So calling something "grade 1" is meaningless in the absence of a definition of which scale is to be employed.

Ah ok I don't know. I just know it's pine and from Finland

For pine, it looks like a nice quality. Pine is KNOWN for its knots. These appear small and tight. That's what you are looking for.

From what I recall #1 common pine had allowed solid tight knots up to 1".