120mm vs 150mm Petty Knife: Which One is Right for You?

TL;DR: 120mm petty knives excel at precise detail work like in-hand paring and trimming. 150mm models offer more versatility for both detail tasks and light utility work. Choose 120mm for maximum control on small ingredients; pick 150mm for balanced performance across various kitchen tasks.

Many home cooks and professional chefs face the same dilemma when selecting a petty knife. The size difference between 120mm and 150mm might seem small, but it creates distinct advantages for different cooking styles and tasks. This comparison examines the geometry, performance, and practical factors that determine which size fits your kitchen needs. Our precision-forged petty knives showcase how traditional Japanese craftsmanship meets modern blade geometry to deliver exceptional cutting performance in both sizes.

1. Detailed Specifications & Geometry: 120mm vs 150mm Petty Knives

The 120mm petty knife offers a compact profile that prioritizes maneuverability. Its shorter blade creates a nimble tool perfect for intricate work where precision matters more than cutting speed. The reduced weight keeps hand fatigue low during extended detail sessions.

For a practical reference point for a 120mm petty, see our Petty HAP-40 Polished, Buffalo Horn Ferrule, Ebony Handle—an illustrative example for size, balance, and everyday prep tasks.

The 150mm version provides additional cutting edge length. This extra reach can allow for longer strokes and potentially more efficient cuts on medium-sized ingredients. The slightly taller blade height may also offer improved knuckle clearance on cutting boards, depending on the specific knife design.

Both sizes typically feature thin blade geometry behind the edge. In some cases, 150mm models may have a slightly more substantial spine to maintain structural integrity across the longer blade length, though this can vary by manufacturer. This balance ensures both sizes remain responsive while providing adequate strength for daily kitchen tasks.

2. Cutting Performance & Technique: How Size Impacts Tasks

120mm Excels At:

• In-hand fruit peeling and segmenting
• Precise herb trimming and brunoise cuts
• Garlic and shallot mincing
• Small fish cleaning and filleting
• Strawberry hulling and berry prep

150mm Handles Better:

• On-board slicing of small vegetables
• Trimming larger proteins like chicken breast (the longer blade can be more suitable for handling larger items)
• Slicing apples, pears, and citrus fruits (the longer blade may offer more slicing length and leverage)
• Light utility tasks that benefit from extra reach
• Portion cutting for appetizers

The 120mm size encourages a controlled pinch grip close to the blade heel. This positioning maximizes precision but limits stroke length. Professional pastry chefs often prefer this size for delicate garnish work and fruit preparations where accuracy is essential.

The 150mm model allows for longer, more efficient cutting motions. Its extended reach makes it practical for tasks that bridge the gap between detail work and light utility cutting. Home cooks who want a single knife for most small-to-medium tasks often find this size more versatile.

For a 150mm reference, explore our Petty SG-2 Kurouchi Tsuchime with Buffalo Horn and Ebony handle—an excellent benchmark for reach, control, and versatility overall performance.

3. Kitchen Space & Cutting Board Compatibility

Small Kitchen Advantages:

• 120mm fits comfortably on compact cutting boards (such as 8x10 inches or smaller)
• Requires less storage space in knife rolls or blocks
• Better control in cramped prep areas
• Ideal for apartment kitchens with limited counter space

Larger Kitchen Benefits:

• 150mm maximizes efficiency on medium to large cutting boards (for example, 12x18 inches)
• Extended reach can reduce repositioning when working on larger boards
• More productive for high-volume home cooking
• Professional kitchens often prefer this size for versatility

Board size directly impacts cutting technique effectiveness. On smaller boards, the 120mm prevents overhang and keeps cutting motions within the workspace. The 150mm shines on larger surfaces where its extended reach becomes an advantage rather than a limitation.

Storage considerations also matter for many home cooks. The compact 120mm fits easily in knife rolls or small magnetic strips. The 150mm requires slightly more space but offers greater utility, making it worth the extra storage requirement for most users.

Learn more: Petty Knife Length: Which Size Is Best for Your Needs?

4. Sharpness, Edge Retention & Maintenance Differences

Edge Maintenance Factors:

• Shorter blades can be easier to maintain due to their compact size
• 120mm requires less time for complete sharpening sessions
• 150mm provides more working edge before noticeable dulling
• Both sizes benefit from regular honing between sharpenings

Edge retention is influenced mainly by factors such as edge angle, thickness, steel hardness, and blade geometry, rather than blade length alone. The 120mm's compact edge may be easier to keep sharp with proper use and maintenance, and sharpening sessions are typically quicker due to the shorter blade.

The 150mm offers more usable edge length, meaning slight dulling in one section doesn't immediately impact overall performance. This characteristic makes it more forgiving for home cooks who sharpen less frequently. However, the longer blade can take more time and attention during sharpening sessions.

Both sizes work well with whetstones in the 1000-3000 grit range for regular maintenance. The 120mm is often easier to maintain consistent angles on due to its shorter length, while the 150mm may require a bit more care to sharpen evenly across the full edge.

5. Conclusion

Choose a 120mm petty knife if you prioritize precise detail work, have limited kitchen space, or often cut in-hand for maximum control. Pick a 150mm petty for more balanced versatility, combining precision with light utility for most small-to-medium prep. We offer VG-10 petty options and an SG2 petty at 150mm, delivering strong edge retention—choose based on cooking style, space, and ingredients.