Unless, of course, you're the person who already bought it from etsy seller Blueflowervintage.
Sibast's No. 8 chair was first designed in 1953, but I don't know when the kid-size versions were made.
If missing the chance to buy one Sibast kid's chair bums you out, you will definitely not want to click through to Lost City Arts, who sold a set of six.
Perhaps if they get production of the grownup No. 8 going smoothly, the new, grandson-led Sibast Furniture will add a kid-size version next.
Vintage Wooden Danish Modern Child's Chair - SOLD [etsy via dt reader sara]
Set of 6 Danish Childrens Chairs by Sibast Mobler - SOLD [lostcityarts]
Sibast Furniture [sibast-furniture.com]