Inside Fukusaya: Four Hundred Years of Making Castella

A type of sponge cake, soft and gently sweet, castella is now a familiar part of Japanese confectionery culture. It is brought home as a souvenir or given as a gift for someone important. Yet its origins lie far from Japan.

Castella emerged from an encounter between Japan and the Iberian Peninsula in the sixteenth century, when Portuguese merchants and missionaries began arriving in Nagasaki. Over the centuries that followed, its ingredients, techniques, and texture gradually adapted to local tastes.

Today, castella is considered a wagashi, or Japanese confection. Founded in Nagasaki in 1624, Fukusaya is one of the oldest companies still producing it. We spoke with them about how castella became part of Japanese food culture, what has remained at its heart, and how a craft can be carried forward without simply leaving it unchanged.

Portuguese Influence and the Nanban Trade

To understand how castella made its way to Japan, we have to travel back nearly five hundred years. In the sixteenth century, Japan became increasingly connected to maritime trade across East and Southeast Asia. After Portuguese traders first arrived in Japan at Tanegashima in 1543, Portuguese ships began visiting ports across Kyushu, Japan’s southernmost main island. This growing exchange between Japan and European merchants became known as the Nanban trade.

Nagasaki soon emerged as one of its most important centers. From 1571, Portuguese ships began calling at the port, and the Portuguese merchants often arrived alongside Jesuit missionaries. They brought not only goods and technologies but also new cultural and culinary influences.

Among the foods introduced through these exchanges was the confection that would eventually become known in Japan as castella. Its origins are associated with European sweets such as the Portuguese pão de ló and Spanish bizcocho. The latter was a firm, biscuit-like food that could withstand long voyages, while pão de ló was closer in appearance to the soft cake we recognize today.

Once the sweet treat reached Nagasaki, however, its story began to take a different course. It encountered a very different culinary tradition, and Japanese confectioners gradually made it their own. These changes laid the foundation for the castella we know today.

This transformation became particularly important as Japan’s relationship with Portugal began to shift. During the Edo period (1603–1868 CE), the Tokugawa shogunate tightened restrictions on Christianity and foreign influence. Following the Shimabara Rebellion of 1637–38, Portuguese ships were banned from entering Japan in 1639, effectively bringing trade with Portugal to an end. By then, however, castella had already taken root in Nagasaki. It remained in Japan even after the foreign presence that had introduced it was gone.

Early Castella and Its Role as a Luxury Confection

At first, castella was a simple treat made from just three ingredients: eggs, flour, and sugar. Sugar was scarce in Japan and considered a precious commodity, sometimes referred to as “white jewels.” Eggs, too, had long been an uncommon ingredient in the Japanese diet, in part because Buddhist dietary practices discouraged the consumption of animal products. Using such large quantities of these two valuable ingredients made castella an exceptionally expensive confection.

By the early Edo period, it was already associated with elite occasions. Castella was served at gatherings involving the shogunate and the Imperial Court, including a banquet held for Emperor Go-Mizunoo at Nijo Castle, the Kyoto residence of the Tokugawa shogunate, in 1626. It appeared again when Tokugawa Iemitsu, the third shogun of the Tokugawa dynasty, visited the Satsuma domain’s Edo (present-day Tokyo) residence in 1630, and was recorded among the confections prepared for Empress Meisho’s visit to her father, the retired Emperor Go-Mizunoo, in 1635.

How Fukusaya’s Artisans Shaped the Making of Castella

As Japanese confectioners began producing castella themselves, techniques and ingredients were adapted over generations to suit local preferences and conditions, gradually transforming it into something distinctively Japanese. Long-established castella producer Fukusaya puts it this way:

“Originally, it was a confection that came from overseas. Through its connection with Nagasaki’s history, natural environment, and local culture, as well as the ingenuity of the Japanese people, it grew into a confection unique to Japan.”

According to Fukusaya, this evolution can be traced through the ingredients themselves. An early castella recipe from the mid-sixteenth century used roughly equal amounts of eggs, sugar, and flour, resulting in a cake that was thought to be firmer and less sweet than the one known today. From the middle of the Edo period onward, the amounts of sugar and eggs increased, while improvements in sugar quality and the introduction of mizuame (starch syrup) in the Meiji era (1868–1912 CE) contributed to a softer, moister, and sweeter castella.

Some of the techniques developed through this process remain central to Fukusaya’s castella today. “One of the methods that we at Fukusaya still value today is the betsudate-ho. First, the egg whites and yolks are separated, and the whites are whipped thoroughly. The yolks, sugar, flour, and other ingredients are then added. This method produces a more moist and fluffy texture, which is one of the characteristics we value in our production.”

Another distinctive feature is the zarame (granulated) sugar at the bottom of the cake. Rather than simply scattering sugar crystals into the wooden mold before pouring in the batter, Fukusaya incorporates the sugar during mixing. As the batter is worked, the sharp edges of the crystals become rounded, allowing some of them to settle at the bottom during baking. This creates the castella’s characteristic texture while contributing to its rich, refined sweetness. Fukusaya describes this as a distinctive handmade technique developed over many years of practice.

The simplicity of the ingredients also leaves little room for error. Fukusaya’s castella is free of additives, so there is little to disguise an imperfect batch. The result depends on the artisans’ ability to read the ingredients and adjust the process accordingly, allowing the flavor, texture, and color of the castella to speak for themselves.

What appears simple is the result of knowledge passed down through generations. Japanese craftsmanship did not simply reproduce the confection that arrived from overseas; it transformed it into something rooted in Japanese food culture.

What Tradition Means at Fukusaya

Fukusaya has continued making castella for more than four hundred years. Yet making it today has never meant keeping every tool or technique exactly as it was. Instead, the company sees tradition as a balance between continuity and change.

“One of the ideas that we at Fukusaya value is fueki ryuko. Even as times change, some things should remain unchanged, while others need to evolve with the times. By carefully and steadily discerning between the two, we have continued to make and offer castella to this day.”

The distinction can be seen in the bakery itself. The methods and skills behind Fukusaya’s characteristic taste have been passed down, while equipment, hygiene management, quality control, and the working environment have evolved. The large charcoal-fired ovens once used to bake castella, for example, have been replaced by electric ones.

“What we have valued is not simply preserving the methods and techniques exactly as they were. It is the spirit of craftsmanship—delivering even more delicious castella to our customers. We have always held on to the wish to bring them joy.”

Modern equipment may have changed the working environment, but much of the work still depends on the judgment of individual artisans. Eggs do not behave exactly the same way every day, while temperature and humidity affect the condition of the batter. Even baking cannot simply be reduced to a fixed number of minutes: artisans must observe the color and height of each cake and make adjustments as necessary.

The same standard has to hold across locations as well as across generations. Fukusaya’s castella is now made in Nagasaki, Tokyo, and Fukuoka, and artisans from each site regularly exchange opinions, give feedback on each other’s castella, and work together to maintain consistency wherever it is made.

This is why much of the process remains in the hands of the artisans. When training the next generation, Fukusaya teaches not only the sequence of operations, but also why each step is necessary and what to look for when making a judgment. Apprentices watch experienced craftspeople, work with their own hands, make mistakes, and gradually develop their own understanding of the craft.

“The experience and wisdom cultivated by those who came before us are passed on to the next generation, and the artisans who inherit them go on to build on that experience themselves. Through this repetition, we have been able to preserve and carry forward both Fukusaya’s taste and the spirit of craftsmanship to this day.”

That spirit extends beyond the making of castella itself. It is also reflected in the company’s annual Tamago Kuyo, a memorial service for eggs held at a temple near Fukusaya’s main store in Nagasaki. The tradition began in the early Meiji era under Tonomura Seitaro, the twelfth head of Fukusaya, and takes place each year on May 22.

“It’s a day to express our gratitude for the many eggs we use every day and to pay our respects to them. It is also a day to remind ourselves to treat all ingredients and materials with care, to pray for the health of our employees and the continued growth of the company, and to give thanks to the customers who enjoy our castella,” says Fukusaya.

“Connecting Time, Connecting Hearts”

Today, castella is as likely to be enjoyed with an afternoon cup of tea as it is to be chosen for a particular purpose, whether as a souvenir, an apology, or a gift for someone important.

That second role carries its own weight. Fukusaya has received letters from customers who chose its castella specifically because they trusted it would be received well, as an apology or as a way of showing care. A torn wrapper, a misprinted inscription, or a foreign object in the box could turn that gesture into another disappointment instead. For Fukusaya, every stage, from selecting the ingredients to the moment the castella reaches the customer, is part of keeping that trust.

The company has also heard from families for whom castella has become something closer to a memory than a souvenir. Schoolchildren visiting Nagasaki on class trips often take commemorative photographs in front of Fukusaya’s main store. When they return home, it’s not uncommon for parents—and even grandparents—to realize that they have almost identical photographs from their own school trips.

“Castella, connecting time, connecting hearts” is a phrase Fukusaya returns to often. Asked what it means in practice, the company points to the many ways castella brings people together: shared with family, served when welcoming an important guest, or given as a thoughtful gift. Through castella, feelings are passed from person to person, connecting people and generations along the way.

In 2024, marking four hundred years, Fukusaya summed up what comes next in four words: slowly, toward the future.

“We want to carry the history and culture of castella, and the spirit of craftsmanship, forward into the next hundred years.”