I have followed Saw franchise long ago (decade kind of) and didn't even check Jigsaw yet and wanted to catch Spiral: From the Book of Saw but can I understand it?
Is this film able to be understandable solo or do I need to see Jigsaw? Or any other previous film?
There was an enormous amount of effort and thought put into the making of Spiral to have it NOT be Saw IX. A lot of the choices made are actually discussed throughout the Spiral wiki page.
In addition, Spiral was also not meant to be a complete reboot. There still may be a Saw 9, and may also be a sequel to Spiral.
Finally, it also is not a reimagination. It is simply a similar movie where the antagonist is a Jigsaw copycat, and which utilizes the theme of traps giving the victims the choice of death versus voluntary dismemberment/disfigurement/disablement.
In my opinion, as a long time Saw franchise 'fan', Spiral is quite able to be appreciated as a stand-alone movie, however a viewer would better understand the traps if one or two of the original series were previously viewed. It is definitely not a requirement to view all previous 8 movies in the franchise to understand Spiral.
If, as you say, you've seen previous movies in the series, you are perfect as a viewer of this new one. You'll 'get' the concept of the traps and not be completely lost in the why of things.
