How to Slice Fish for Sushi

Slicing fish for nigiri or roll toppings is one of the more difficult parts of making sushi, and will take some practice and patience to master. Some cuts of fish will be more difficult to slice than others, so even though I have a lot of practice, I'm still not always 100% satisfied with the results. Slicing strips of fish to go inside rolls, or mincing fish for mixes like spicy tuna, are relativity simple compared to thinly slicing fish for nigiri and roll toppings.

The links below will jump to each section of this guide, but I recommend reading the whole guide once before beginning.

• Equipment
• Final Products
• Process
• Slicing Fish for Roll Filling
• Mincing Fish
• Slicing Fish for Nigiri & Roll Topping
• Slicing Other Seafood

Equipment

The most important thing is to use a long, sharp knife. The sharper the knife, the easier the whole process will be. I have some suggestions for knives at different price points (as cheap as $20) in my Equipment for Making Sushi at Home guide. You'll also need a cutting board, I recommend using plastic if possible because it's a bit more sanitary than wood for handling raw fish. A kitchen scale will also be useful for determining weights of fish pieces to make sure you're properly following the recipes for things like spicy tuna. There are recommendations for both a kitchen scale and cutting boards in the equipment guide as well!

Process

Determine what you're making

• Before cutting, you should have an idea of how you plan to divide the fillet. For example, you may have a 0.5 lb block of tuna and plan to make one batch of spicy (using 0.2 lbs) and slice the rest for nigiri. The recipes on this site all list an approximate weight of fish to use, which should help you divide up your fish.

Clean the fish

• Before slicing, rinse your block of fish under cool water in the sink. Pat it completely dry with paper towels. This step should help improve the flavor of the fish, especially if it has been in the packaging for a few days.

Slice

• Once you have a plan for the fish, and it's clean, place it on a cutting board and start slicing. There are many more details on this below, but my process is typically the following: make the initial cuts to set up my nigiri/roll topping slices, slice the nigiri/roll topping, slice the solid roll filling, then prepare the minced filling.

Slicing Fish for Roll Filling

As stated above, the ideal for this will be a strip of fish with a cross-section of around ¾" X ¾" and a length of 8" (the length of a sushi roll). In reality, it's fine to arrange mismatched pieces to fill the roll, and likely won’t even be noticeable when the roll is finished and cut. This means you can use end pieces and other misshapen cuts as solid roll filling if desired.

If you're just slicing for roll filling and not planning to make any nigiri or sliced fish roll topping, you can simply slice the fillet into approximately ¾" X ¾" cross-section strips. If possible, make these cuts perpendicular to the grain of the fish (this will make the fish less chewy). I'll try to post a video of this at some point, but I'm almost always cutting nigiri and roll toppings, following the method below.

Slicing Fish for Nigiri & Roll Topping

This process will vary depending on the size and shape of your fillet, which is one of the things that makes this difficult. I'll try to update this guide with more examples as I'm able to, to try to cover more scenarios. Here's the general sequence of events:

Clean the fish

• Rinse your fillet in cold water, then pat completely dry with paper towels and place on a cutting board.

Prepare the Fillet

• In general, you want to work with a rectangular fillet like this one.

• You may have a fillet with a shape like the one in the video below. In that case, we want to remove the excess from the bottom of the piece. The part that is removed can be used for solid roll filling or minced filling!

Determining cut angle

• The angle of your cuts will determine the length and width of your finished slices. If you just slice a ¼" thick piece off the end of the fillet, the piece will match the cross-section of the fillet. In most cases, the cross-section is the fillet is smaller than the desired dimensions of ~1.5 inches wide, 3-4 inches long. To get the desired size piece, you need to cut at an angle.
• This part can be a little confusing, so as an engineer, I've jumped on the opportunity to make some diagrams. To visualize it, let's look at adjusting one dimension at a time. (If these diagrams are confusing, watching a few of the slicing videos below may help)

• First, we'll look at adjusting the width of each piece. Imagine you're looking at the fillet from the side, so we can see the thickness and length dimensions.

• Next, we'll look at adjusting the length of each piece. For this example, imagine you are looking directly down on the fillet, so the width and length dimensions are visible.

• If you want to be able to cut consistently sized slices from different sized fillets, you'll have to understand how the angle of your cuts affects the size. Don't worry if this doesn't make sense right away, this is a more advanced technique that you don't need to master right away.
• For most fillets you'll need to make adjustments in at least one direction, and often you'll need to do both at once. The video below is an example of how to slice a fillet to increase both dimensions. The angle to increase length (like cut C) is pretty extreme, while the angle to increase width (like cut B) is only slight.

Slicing Technique

• Use your non-dominant hand to support the slice.
  • If you're right-handed (like the example videos) you'll hold the knife in your right hand, and cut pieces off the left side of the fillet. This feels a bit unnatural because typically you cut off the right side of an object if you're right-handed. Normally you would use your left hand to hold the bulk of thing you're cutting, but for slicing fish you use your left hand to support the thin slice you're making.
  • If you're left handed, you'll do the opposite. Hold the knife in your left hand, slice pieces off the right side of the block, and use your right hand to support the slice.
• Pull the knife towards you.
  • Most Americans are used to using a pushing motion when cutting, but for slicing sushi fish you want to use a pulling motion. Start the cut at the base of the blade and pull the knife towards you as you cut.
• Do NOT saw the blade back and forth.
  • Ideally, if your blade is long enough you can make the cut in one stroke. If that's not possible, don't change direction and push the blade away from you. Instead, pick the knife up off the fish, and restart the cut with a pulling motion to cut the rest of the way through.

Below is another example, this time with Maguro (bluefin) tuna.

Slicing Other Seafood

Sea Scallops

To prepare a sea scallop, cut off the small side, then butterfly the scallop. To butterfly, slice the scallop in half as shown in the video below, but do not go all the way through. If you do cut it all the way through it's still fine, it just might not hold together as well when you use it.

Octopus

You can purchase prepared octopus at a Japanese grocery store. At this time I don't have a guide to making this from scratch. This type of octopus is fully cooked, and usually packaged as "Octopus Sashimi".

Slicing octopus is similar to slicing other sushi fish, however in this case it's okay to saw the knife back and forth. Sawing the knife gives the octopus slice a little bit of texture which is considered desireable.