Peening is extruding material from the blade and then flattening the very edge to make it very thin and therefore very sharp.
This is a really good mirror-polished anvil, which should be used with an equivalent mirror-polished peening hammer.
The great advantage of using this tool is that it is also good for repairing the blade if you have damaged it by hitting stones or wire and have nicks in the edge.
This peening jig also has guides, helpful for beginners.
Link to video on using the anvil with platform (support)