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Longzon 4-stage Manual Knife Sharpener In-depth Review

The Longzon knife sharpener has a solid construction and produces a smooth edge, but it didn’t perform so well in our sharpness tests.

By , , and ·Updated
Tested Using Methodology v1.1
The Longzon 4-stage knife sharpener on a cutting board, kitchen knife, chilli peppers, carrot slices, tomato slices

Overall Verdict

The Longzon 4-stage sharpener is a well-made device with solid build and great usability. It’s gentle on your blade and the beautiful edge it creates can hardly be matched by any other devices of its type.

Unfortunately, it didn’t perform so well on the sharpening front in our tests. The device will not be a good choice if you want remarkable sharpness and even less so if you want it quick.

Things We Like

  • Sleek design
  • Substantial, accommodative size
  • Fine, smooth knife edge
  • Inclusion of protective gloves
  • Slot for scissors

Things We Don’t Like

  • Tall base
  • Slow sharpening
  • Ineffective slot layout

The Longzon sharpener is a good example of how competitive it has become in the world of knife sharpeners: We bought it for under $15 (sale price), and it comes in an attractive box with a pair of cut-resistant gloves. The device itself is well-made with quality materials.

But a strong and stylish build doesn’t always translate to excellent sharpening results. As our tests revealed, the Longzon sharpener is evidence of this.

Key Specs

Scissor sharpener
Diamond, tungsten carbide, ceramic
Grit size
Coarse, Medium, Fine
L9.3 x W1.8 x H3.1 inches

Where to Buy Price at publication $13.30

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Compared to Other Manual Knife Sharpeners

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Analysis and Test Results

5.6 Performance

The Longzon 4-stage knife sharpener creates one of the finest edges we’ve seen with a device of this type. Unfortunately, the edge’s functionality doesn’t match up with its aesthetics. It only became keen after more than 3 minutes of sharpening, and a prolonged sharpening time didn’t get it much further on the sharpness scale either.

1.0 Sharpening Time to Cut a Lemon

Sharpening Time
3 minutes 10 seconds
Cutting Feel
Swift and smooth

The Longzon sharpener was disappointing in this test: It took 190 seconds on average to sharpen a dull knife to the level where it can slice a lemon with ease. Three minutes doesn’t seem so long, but when you’re repeating a motion on a small device, it can feel like an eternity.

Unlike the case with the Mueller, the tungsten carbide blades on this device offer a tight and steady brace. For some reason unknown to us, the knife edge just didn’t get keen quickly enough with it.

6.0 Maximum Sharpness Achieved

Sharpening Time
6 minutes
Sharpness Level
7 (ripe tomatoes)

We doubled the time in the lemon-cutting test and the Longzon sharpener could only up the knife sharpness by one level. It cut through a ripe tomato effortlessly, and took two forceful swipes to sever the tough skin on a chicken breast. This isn’t a bad performance, per se, but we had expected more from the sharpener as it looks so well-made.

9.0 Edge Smoothness

Longzon Knife Sharpener Edge Smoothness

We couldn’t be more impressed when we saw the knife edge after sharpening with the Longzon. It’s smooth, shiny, and balanced between the two sides — common among electric sharpeners, but a rare thing to see with manual pull-through devices. We can’t quite explain the lack of chips, grains, or unfinished shavings — we didn’t need a magnifier to see them on the edge produced by its identical cousin, the Mueller. 

At any rate, if a clean, perfect edge is what you’re after in a handheld sharpener, the Longzon should be among your top choices.

9.0 Material Retention

Metal residue in the sharpening slots of the Longzon knife sharpener
Metal residue in the sharpening slots of the Longzon knife sharpener
The Longzon household knife sharpener next to a bowl containing metal dust residue
Sharpening Time
1 minute

On most devices that employ tungsten carbide blades as the sharpening ‘abrasive’, the more material they remove, the quicker they work and the sharper the edge. The Longzon is not an exception. It took more than 3 minutes to produce a keen edge, so it’s not a complete surprise that it only removed a moderate amount of material from the edge in 1 minute.

9.1 Design

The Longzon looks identical to the Mueller handheld sharpener and has a much better build and design than its affordable price suggests. There’s no shoddy parts or gimmicky details — everything fits together securely and seamlessly to serve its purpose.

We also like the device’s substantial size which allows for easy sharpening of larger kitchen knives. The inclusion of the gloves is nice, though we didn’t feel the need to use them.

In the Box

The Longzon knife sharpener lying next to its package box, instruction leaflet, and two gloves
  • The Longzon 4-stage knife sharpener 
  • Instruction manual
  • Protective gloves 

The Longzon sharpener comes in a nice cardboard box with lots of instructions and contact information printed on it. Then there’s a leaflet that features the instructions in five different languages. Two thin gloves are included in the package, presumably for protecting your hands during sharpening, though this is mentioned nowhere in the manual.


The Longzon household sharpener with arrows and figures showing its dimensions.
9.3" (23.6 cm)
1.8" (4.6 cm)
3.1" (7.9 cm)
8.7 oz (246 g)

9.1 Build Quality

The Longzon sharpener standing on a surface

The Longzon sharpener has a strong build with quality materials and a robust design. Its working section, handle, and base are securely attached to each other, which helps with stability during sharpening. The design is function-oriented, but everything has a nice, flush finish. We couldn’t expect better, especially for its price.

Working Section

Longzon Knife Sharpener Working Section
Levels of Sharpening
Sharpen, Hone, Polish
Tungsten carbide blades, diamond rods, ceramic rods
Pull through
Sharpening Angle
20 degrees

The working section features one slot for scissors and three for kitchen knives. Instead of a prep slot, you start sharpening your knives with the tungsten blades and use the diamond and ceramic rods for further honing.

The whole working section is covered with stainless steel, making it easy to clean should the need arise.

9.0 Grip

Longzon Knife Sharpener Grip

The Longzon has a nice, substantial grip. There’s plenty of space for larger hands or for those who want their gripping hand to be as far away from the knife as possible while sharpening.

The upper side of the grip is a plastic that’s very soft to the touch and has decent friction. The lower side features finger nubs for a firmer grip.


The Longzon sharpener lying on a surface with its base in full view
The Longzon sharpener lying on a surface with its base in full view
Part of the base of the Longzon manual knife sharpener
Feet Type
EVA feet

The Longzon has a red ABS base that makes it look like a Louboutin shoe. It tapers from the working section downwards, but the base size is sufficient to keep the device in place. 

It boasts two flat, but effective, anti-slip pads underneath the working section and the grip.

8.2 Ease of Use

The Longzon is straightforward, and there are visual cues on the device if you’re not sure how to use it at first glance. Its large grip and wide working section make sharpening natural and effortless. Though we think a more modest height would make it safer to use, its stability is well above average.

7.0 Slot Arrangement

The working section on the Longzon handheld sharpener, with 1 slot for scissors and slots 2, 3, 4 for knives

The Longzon’s layout of sharpening slots is identical to the Mueller, and in our experience, not ideal. We’d rather move Slot 3 (diamond rods) to the front of the row to serve as a prep slot.

Otherwise, the arrangement is simple and easy to work with — all the slots have the same grind angle and are designed for the same types of knife edge. The natural progression of coarseness (or fineness) level means you never have to pause halfway through in fear of going the wrong way.

9.0 Insertion

Top view of a kitchen knife being sharpened using the Longzon with 2 hands holding them

Insertion was easy with the Longzon: Its wide slots with a neat design offer enough space for the blade to get in without obstruction. You may cut into the wall if you go too fast, but that should be rare.

8.0 Pulling Through

A kitchen knife being sharpened with the Longzon, and the 2 hands that hold the knife and the sharpener

With the U-shaped plastic frame placed too close to the sharpening rods, we ended up cutting into them after almost every swipe. Even a few more millimeters would avoid this. But other than that minor annoyance, the Longzon offers a great sharpening experience. Its blades and rods provide a steady brace with decent and stable friction that’s evident in the near-perfect knife edge it creates. It’s also effortless to keep the blade straight during sharpening — we never ended up with an uneven edge, as was the case with its Mueller counterpart.

8.5 Stability on a Clean Surface

A hand holding the Longzon on a kitchen countertop and sharpening a knife with it.

Even though the base is tapered, it’s still large enough to support the sharpener. The rubber pads offer good contact areas and great friction, so the device wouldn’t slip on a countertop. We didn’t have to use excessive force to keep it steady during sharpening, just a firm grip.

8.0 Stability on a Wet and Dirty Surface

A kitchen knife being sharpened with the Longzon on a countertop with salt particles

The slippery countertop wasn’t much of a challenge for the Longzon either. It did glide a bit when we intentionally used more force to sharpen, but it fared well most of the time.

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