Fried Marlin (Kajiki) with Savory Japanese Aurora Sauce

🐟Fried Marlin (Kajiki) with Savory Japanese Aurora Sauce

This dish is a beloved “soul food” found in Japanese school lunches (Kyushoku). While traditionally a hit with children due to its meat-like texture, this version adds whole-grain mustard to create a sophisticated flavor profile that adults will love.

📝 The Story Behind “Kajiki” (Marlin & Swordfish)

In Japan, these fish are collectively called “Kajiki Maguro.” Here is everything you need to know about them:

Not Actually Tuna: Despite the name, they are a different species from tuna (Maguro). They are called “Kajiki Maguro” because they share similarities like large size, high migration, and premium meat quality.
The Speedsters of the Sea: They are among the fastest sprinters in the ocean, with some species reaching speeds over 100 km/h.
Easy to Cook: Kajiki is often sold with the skin and bones already removed. Its light, lean flavor makes it incredibly versatile—it pairs perfectly with butter, garlic, soy sauce, or miso.

Classification and Characteristics of Billfish & Swordfish

Kajiki maguro	Billfish (Makajiki)	Swordfish (Mekajiki)
Scientific Family	Perciformes: Istiophoridae	Perciformes: Xiphiidae
Species	11 species (Marlin, Sailfish, etc.)	1 species (Swordfish only)
Japanese Name	Makajiki	Mekajiki
Taste Profile	Of all kajiki maguro, the marlin is considered the most delicious.	Known for its rich, fatty texture; very popular.
Peak Season	Summer	Winter
Availability	Difficult to obtain outside of its peak season.	Available year-round (mostly sold frozen).

Quick Culinary Notes

Marlin (Makajiki): Often praised for its firm texture and elegant reddish flesh, making it a high-end choice for sashimi or sushi.
Swordfish (Mekajiki): With its high fat content, it stays moist and tender even when sautéed or grilled, making it a versatile favorite for home cooking.

🥗 Nutrition Facts (Per Serving); Fried Marlin (Kajiki) with Savory Japanese Aurora Sauce

Calories: 216 kcal
Protein: 20.5g
Fat: 8.5g (calculated with an 8% oil absorption rate)
Carbohydrates: 10.4g
Salt Equivalent: 2.0g

🛒 Ingredients; Fried Marlin (Kajiki) with Savory Japanese Aurora Sauce

Main: 100g Marlin (or Swordfish)
Seasoning: 1g Grated Garlic, 0.5g Salt
Coating: 4g Flour (I recommend “Cooking Flower” for a crispy, non-sticky finish)
The Sauce:
- 10g Tomato Ketchup
- 10g Worcestershire Sauce
- 3g Whole-grain Mustard
Cooking Oil: Moderate amount

I recommend cooking flower, which is less sticky and can be fried deliciously with less oil.

👩‍🍳 How to make Fried Marlin (Kajiki) with Savory Japanese Aurora Sauce

Prep: Rub the grated garlic and salt onto the fish, then dust evenly with flour.
Fry: Heat oil to 170°C (340°F). Fry the fish until it turns a beautiful golden brown.
Sauce: While the fish is frying, mix the ketchup, Worcestershire sauce, and grain mustard in a bowl.
Finish: Drain the excess oil from the fish and toss it immediately into the sauce until thoroughly coated.

💡 Chef’s Memo: What is Aurora Sauce? In Europe, “Aurora Sauce” is traditionally a Béchamel base with tomato. However, in Japan, it almost always refers to a Ketchup and Mayonnaise mix. In this specific recipe, we use Ketchup and Worcestershire sauce to create a deeper, savory glaze that complements the “meaty” texture of the marlin perfectly.

🍤 You Might Also Like… If you want to try the classic Japanese-style Aurora sauce—the popular combination of ketchup and mayonnaise—don’t miss this recipe! These succulent shrimp fritters coated in a rich, creamy sauce are absolutely addictive.👉 Ebi Mayo (Fluffy Shrimp Fritter With Japanese Aurora Sauce)

📖Related Link: Read the Japanese version of this article here! []　　　

naokoan

Hi, I’m Naoko! I am a licensed Registered Dietitian in Japan, currently working in a hospital setting. My daily mission is to provide nutritious, healing meals to patients, ensuring that every dish supports their health and brings a smile to their face. My recipes are more than just cooking guides—they are built on scientific nutritional balance and clinical experience. Why I provide ingredients in grams (g): You might notice that all my recipes use precise gram measurements. This is because, as a dietitian, I believe that accuracy is the key to true health management. Whether you are tracking calories, managing salt intake, or simply want to recreate the exact flavor of a professional hospital kitchen, these measurements ensure your success and well-being. My Specialty: I specialize in high-pressure cooking and oven recipes that save time without sacrificing nutrition. My goal is to introduce the world to “Real Japanese Home Cooking”—dishes that are simple, budget-friendly, and body-friendly. I’m thrilled to share the wisdom of Japanese nutrition with you. Let’s cook our way to a healthier life!