Step 1

Place a rule along your waterstone to show any hollowing.

Steel rule across a waterstone showing a hollow in the centre

Step 2

Using a pencil scribble on the face of the stone. This will give you a clear visual guide of how flat your stone is becoming.

A scribbled pencil line along the waterstone

Step 3

Using a ceramic flattening stone run along the face of the waterstone. Dipping in water rinses away residue.

A ceramic flattening stone rubbing a waterstone over a bowl of water.

Step 4

Cutting away the high points leaves only the pencil markings where there are still hollows.

Ceramic flattening stone next to japanese waterstone with pencil line.

Step 5

It's important to keep checking the flatness of the stone throughout the process.

Step 6

Continue until the pencil lines have disappeared.

Worn pencil line on Japanese waterstone.

Step 7

Check for final flatness.

Steel rule on Japanese waterstone showing stone completely flat.