Step opening open staircase / child protection > 12 cm?

The DIN standard doesn’t help you, make it safe for your child.
From 8 months on, they climb up and down there if the path is clear

And precisely for this reason, the path should not be clear until the toddler can safely go up and down the stairs on their own.
Anyone who lets their 8-month-old child climb on the stairs alone is, with all due respect, really to blame themselves.

The spacing between the vertical bars on the railing is just right, measured straight. But why don’t you see that as comparable?

Because one is a quickly happened and likely accident, while the other is self-endangerment combined with an almost criminal energy that intellectually overwhelms such a little one. And as I said, even if the cat did it and showed the child how, the child simply wouldn’t have fit here. The child would have to be so flexible that, conversely, it could still demonstrate something to the cat, and even then, there was still a lack of potential energy for a real danger. Falling acceleration and lateral acceleration are two different things. The accident you fear is exclusively virtually simulatable. Sliding through between bars with a leg or arm so that even green wood breaks will, however, already have happened and initiated the regulation.

My concern for the kindergarten teachers’ psyches in view of hysterical parents is probably more real than I feared earlier.

The distance between the railings is based on head width. Children should not be able to stick their heads through the railing. My grandmother stuck her head through an iron railing as a child, and her father had to be fetched from work to bend the railing apart. The dented railing bars were shown to every visitor.