2 Egg cartons and an empty washing up liquid container

Handy alternative for your knife holder seen in a few Sushi bars is this:

Get last year's phone directory and run some masking tape around the front and back from top to bottom making the pages nice and tight together. Then pop it amongst your cookbooks, spine to the wall and pop your knives in it. Apparently keeps rust from non stainless steel knives and may have a tiny sharpening effect.

Works well, just have to be carful not to walk into the handles and remember to ask a parent for help if using sharp objects