Chase Kojima’s Guide To Making Sushi

Sokyo’s head chef Chase Kojima shares his how-to guide on preparing and eating perfect sushi to help you master this culinary art.

I learnt how to make sushi from my dad, who ran what I think was the best Japanese restaurant in San Francisco. There’s a lot of technique to making really premium sushi and it requires practice to master – working at it until it becomes a muscle memory. Here’s how we do it in the restaurant, with a few tips for making it at home.

1. The seafood

This can be anything from fish to scallops, lobster or even clams. In the days before refrigeration, it was cured using salt to draw out excess moisture, and vinegar to kill any parasites, but now we just buy it really fresh. It’s best to use premium fish with a good fat content for more flavour. Toro, the tuna belly is very popular, but we also use salmon, snapper, kingfish and even sardines. We tend to dice it finely for aesthetic reasons, but you can do it to the size you prefer.

2. The rice

Sushi rice has a very short grain and a slightly sweet flavour. I prefer older sushi rice, which seems counterintuitive, but the crop from the end of the season is the best – it’s dryer and works better in sushi. If you buy sushi rice from a Japanese store or supplier, it will usually have the date it was harvested on it.

It’s important to wash the grains very carefully so you don’t break them up. We put it in a bowl and mix it with water, changing the water five times. Then we add filtered water, usually at a ratio of 1 to 1, but we might adjust that by 10 to 20 per cent depending on how dry the rice seems. Then it’s soaked for around 20 minutes. In my dad’s restaurant, he would put it in a pot on the stove on high until it started to boil, then turn it to a very low heat to simmer for around 25 minutes. In the restaurant, we make it in a rice cooker, which takes about 20 to 30 minutes.

3. Mixing

When the rice is done, we put it into a bowl with seasonings – good quality rice vinegar, salt and sugar (and a couple of secret ingredients I’m keeping to myself!) Then we mix it evenly and quickly. You don’t want to do it with too much movement or it will bring out the gluten and the rice will be sticky. Once we’ve mixed it, we use a fan to bring it down to room temperature and to stop it cooking further through ambient heat.

4. The seaweed

Honestly, it’s difficult to buy the calibre of seaweed you get in Japanese restaurants, but if you’re making it at home, have a look for the most expensive you can find in a Japanese market – it really does make a difference! Good seaweed is pliant and melts in the mouth, while still maintaining some body rather than going soggy.

5. Rolling

We use a typical bamboo mat. Most chefs will use the ‘rough’ side for speed, but I prefer the other, smoother side up. Place the seaweed on the mat, and take about 100-120g loosely packed rice, (about the size of two eggs) and spread over the sheet, except for about a centimetre at the top. In the restaurant, we often use more protein and less rice, although my dad would not necessarily approve of that!


Put your protein and anything else, such as avocado, cucumber, or maybe some blanched asparagus into the centre and roll. The first time you roll the sheet just to cover the filling and seal it in. The second roll, you roll all the way to the top of the seaweed, creating a small overlap. Don’t roll too tightly and don’t keep touching it or moulding it – it doesn’t need to be perfect.

6. Cutting

Naturally in Japan there is a special sushi knife! Known as a ‘yanagiba,’ they cut very cleanly and can cost as much as $4,000. Any sharp knife will do, however. Dip the blade into a bowl of water then tap the handle onto a cutting board so the water travels down the length of the blade. Cut swiftly down the middle to make two halves, then two more times to cut into six pieces.

7. Eating

In a Japanese restaurant, the chef will normally have seasoned the sushi already, but you will often be given some small bowls with extra soy sauce, ginger and perhaps wasabi, if it’s not already inside the roll. Choose a soy that’s not too salty and be judicious with its use – you want to taste the ingredients, not just salt. In the restaurant we also add some bonito, kelp and a secret ingredient or two.

Don’t pour the soy all over the roll, you want to just season the protein a little bit, so dip your sushi into the soy to moisten it. In between bites or different rolls, take a little pickled ginger to cleanse the palate.

And there you have it. While we strive for aesthetic perfection in the restaurant, when making it at home, please feel free to practise the Japanese philosophy of ‘wabi-sabi’ – embracing the beauty of simplicity and imperfection.

Book your next dinner date at Sydney’s beautiful Japanese restaurant, Sokyo, and experience Chase’s insane cooking for yourself.