The sharpener built into the block, explained

What lives in that slot

On 16 of our 19 sets, one slot in the block is not a slot at all; it is a pull-through sharpener built into the wood. Draw the blade through a few times and two preset abrasive wheels stand the edge back up at the factory angle.

The point is not that it sharpens better than a stone. It does not. The point is that it is there, so it gets used. A stone in a cupboard sharpens nothing; a slot you pass every day keeps the whole rack working.

How to use it without overusing it

Three to five smooth pulls, light pressure, full length of the blade from heel to tip. Do it when tomatoes start to squash instead of split, which for a home kitchen is every few weeks, not every day. A pull-through removes real steel; daily passes shorten a knife for no gain.

Between sharpenings, a honing rod is the gentler tool: it realigns the edge without grinding it. Rod weekly, slot monthly is a fair rhythm for a busy kitchen.

Where the built-in stops

• Serrated blades, bread and steak knives, should stay out of the pull-through; the teeth do not fit the wheels and hold their bite for years untouched.
• A chipped or rolled edge needs a proper stone or a professional pass. The slot maintains an edge; it does not repair one.
• No sharpener in your set is not a problem, just a purchase: any decent pull-through does the same work from a drawer.