Why Did My Knife Chip or Go Dull?

Knives come across our sharpening bench in Brisbane every week, and the same handful of causes explain almost every chipped or dull edge we see. This guide helps you work out what happened to yours, what you can fix at home, and when to bring it in.

First, which one is it?

Run the edge very gently over a fingernail or look at it under a bright light, edge pointing up. Dullness shows as a fine line of reflected light along the apex. Chips show as bright spots or visible bites in the edge line. The distinction matters, because the causes and fixes are different.

Why knives go dull 

• Normal use. Every edge dulls with cutting. It is not a fault, it is physics. Hard steels like the ones on Japanese knives just dull slower.
  
• The cutting board. Glass, marble, ceramic and bamboo boards are edge killers. So is a plate. Wood and soft composite boards are the only surfaces your knife should touch.
  
• Scraping. Sweeping food sideways off the board with the edge rolls the apex over. Flip the knife and scrape with the spine.
  
• The dishwasher. Heat, harsh detergent and rattling against other cutlery. Never.
  
• A pull-through sharpener. These feel like they help, but they tear steel out of the edge and leave a weak, ragged apex that dies within days. On hard Japanese steel they can chip it outright.

The fix for dullness is simple: sharpen it on whetstones. Our step-by-step guide shows how, our classes teach it hands-on, and our sharpening service does it for you.

Why knives chip 

• Hard contact. Bones, frozen food, fruit pits, pumpkin and squash necks, crab shells. Japanese blades are thin and very hard, which is why they cut so well, and also why they chip instead of bending when they hit something harder than food.
  
• Twisting. Prying apart a split pumpkin, levering frozen blocks, twisting through a melon. The edge is not a lever.
  
• Sideways force in the drawer. Loose knives knocking against other tools chip edges while you sleep. Use a saya, a stand or a knife roll.
  
• Sharpening damage. Too much pressure on coarse stones, or a pull-through sharpener on hard steel.
  
• Rarely, the knife itself. Very hard, thin edges on some high-hardness steels can micro-chip in their first weeks until the factory edge is sharpened past. If chipping seems constant and unexplained, bring it in and we will look at the geometry.

What you can fix at home

• Dull edge: a normal session on a #1000 stone, refined on a finer stone. See our sharpening guide.
  
• Micro-chips (you can feel them but barely see them): sharpen normally on a medium stone; a few extra passes will erase them.
  
• Visible chips, bent tips, broken tips, cracks: workshop jobs. Repairing a chip means removing steel across the whole edge to keep the profile straight, and doing it freehand without changing the knife's geometry takes practice. This is the bulk of what our sharpening service does, chips and broken tips included.

Make it not happen again

Wood or soft composite board. No bones, no frozen food, no twisting. Hand wash, dry, store protected. Sharpen little and often on stones rather than rarely and drastically. That routine is covered in our knife care guide, and it is genuinely all there is to it.

Not sure what you are looking at? Email a photo of the edge to contact@japaneseknifestudio.com.au or bring the knife into the studio at Lot 10, 198 Adelaide Street, Brisbane City. Diagnosis is free and takes about thirty seconds.