Kochi V2 kurouchi 180 mm nakiri: what it is and how to look after it
"Kochi V2 ku 180 nakiri" is shorthand used in knife forums for a specific carbon-steel vegetable knife: a 180 mm nakiri in V2 steel with a kurouchi ("ku") finish. The details below separate what a retailer documents from what is guesswork, because the name "Kochi" invites assumptions.
In this guide
What "Kochi" refers to
Kochi is the name of a prefecture on Shikoku, but none of the pages read for this guide say the knives are made there. The retailer that sells the line, Japanese Knife Imports, states that it is exclusive to that shop. The nakiri product description does not identify the smith; image names or captions alone should not be used to attribute it to Wakui.1 The line includes deba, wa-petty and yanagiba as well as nakiri.2 Treat "Kochi" as a retailer-exclusive line name and check the seller's description for the actual maker, rather than assuming a Kochi Prefecture origin.
What V2 means
V2 is a carbon steel from Takefu Special Steel, a Japanese producer. Its published composition is about 1.00% carbon, up to 0.40% chromium and up to 0.25% nickel.3 Reference sites describe it as a relatively simple alloy, capable of 63 to 64 HRC, positioned as a sort of replacement for Hitachi White (Shirogami) #2, though not as pure as the Hitachi grades.4
Do not confuse V2 with "V-Toku 2", which is a different Takefu grade with tungsten and vanadium (about 1.05% carbon, 1.25% tungsten) and is closer to Blue #2.3 A listing that says "V2" should mean the plain grade. Yoshikane's Tamamoku line is another documented user of the same steel.4
Construction, finish and geometry
The retailer lists the 180 mm nakiri as carbon steel with reactive carbon cladding ("not as reactive as many") and ambidextrous. Measured values on that page:1
| Item | Listed value |
|---|---|
| Blade length (heel to tip) | 184 mm |
| Handle-to-tip length (excluding handle) | 197 mm |
| Height at heel | 53 mm |
| Spine width, middle | 2.04 mm |
| Weight | 185 g |
| Handle | Burnt chestnut, octagonal |
The seller describes the knife as substantial near the spine but extremely thin behind the edge, which is typical of a good vegetable knife.1 These are measurements of one retailer's sample, so expect small unit-to-unit variation.
Kurouchi means "black forged": the dark forge scale left on the blade instead of being polished away.5 The finish gives some surface protection and hides scratches, but it is chiefly visual; it does not stop the exposed edge and cladding from reacting.5 Natural kurouchi can wear and transfer slightly during early use, which is normal rather than a defect.5
What a nakiri is for
A nakiri has a flat edge and square tip, designed for vegetables. The Wikipedia entry gives blade lengths of about 16 to 18 cm and notes that the shape lets you cut dense produce right up to the tip.6 That makes 180 mm the top of the usual range, so a 180 nakiri covers a large cabbage or daikon in one pass.
How to use it well:
- Cut with a push-and-down motion or a straight chop. Because the edge is flat there is no rocking.
- Use the full height of the blade as a guide against the knuckles and as a scoop for transferring food.
- It is a vegetable knife. Skip bones, frozen food and hard squash that is cut by prying; a thin carbon edge will chip.
- A wood or soft plastic board suits it better than glass or stone.
Who it suits, and carbon versus stainless
Choose a carbon nakiri like this if you cook vegetables often, accept some patina, and want an easy-to-sharpen edge. Retailer guidance says carbon steel generally sharpens easily and gets very sharp but rusts if left wet; stainless is lower maintenance, while edge retention depends on the particular steel, heat treatment and use.7 The seller of this knife says V2 takes a very good edge, sharpens easily and has good retention (retailer opinion).1 If you want no-fuss care, a stainless nakiri or a semi-stainless steel is a better match.
Care and sharpening
- Wipe during use, especially after onions, citrus and tomatoes, and dry immediately after washing.8
- A grey, blue or brown patina is protective. Orange, rough or powdery spots are rust; remove light rust with baking soda or Bar Keepers Friend paste on a soft cloth, then rinse and dry.8
- Hand wash only, and store dry, ideally with a thin film of camellia or food-safe mineral oil when put away for longer.8
- Do not load a magnetic strip edge-first; load the spine first.8
- Sharpen on a 1000-grit stone, then a 3000 to 5000 grit finishing stone, at about 15 degrees per side, until a burr forms along the whole edge.9 Hold a flat edge level so the full length touches the stone; a nakiri has no belly to hide uneven sharpening.
What to ask about a used Kochi nakiri
Search both Kochi 180mm kurouchi nakiri and the collector shorthand Kochi V2 ku 180. Add Japanese Knife Imports when unrelated knives or location results dominate. If the seller has the purchase email or box label, ask them to use the exact line name from it.
The exposed edge deserves its own photograph. Ask about chips, rust pitting, thinning and whether the blade has been shortened or reprofiled through sharpening. A darker blade face may simply show patina, while uneven edge damage changes the work needed before it is ready for the kitchen. Request a straight profile photograph on a flat surface so that the remaining edge shape is visible.
Is the black finish meant to stay perfect?
The finish is part of the knife's appearance, but a used example should be assessed as a tool as well. Ask whether cosmetic changes came from normal use or abrasive refinishing. Decide in advance whether preserving the original finish is important to you; polishing an old blade and then trying to restore its appearance are different projects.
Will it replace a santoku?
It can cover much vegetable preparation, but the rectangular tip changes how you work. Compare it with the 180 mm santoku guide if you want one main knife for a mixture of tasks. Keep a separate tool for jobs that involve bones, frozen ingredients or levering through hard food.
Video demonstrations
Working With Carbon Steel Knives
Sources and further reading
- Kochi 180mm Kurouchi Nakiri, Japanese Knife Imports: retailer page with measurements and description.
- Kochi 210mm Kurouchi Wa-Petty, Japanese Knife Imports: retailer page on the Kochi line.
- Takefu original knife steel, Takefu Special Steel: manufacturer composition table for V2 and V-Toku grades.
- Takefu V2 steel, Zknives: reference description.
- What Is a Kurouchi Knife?, Cutlery and More: retailer explanation.
- Japanese kitchen knife, Wikipedia: types and sizes.
- Carbon vs stainless steel, Chef's Edge: retailer comparison.
- Carbon Steel Knife Care Guide, Chef Knives To Go: retailer care guide.
- How to sharpen a Japanese knife on a whetstone, Knives and Stones: retailer guide.