Castella: Nagasaki's Famous Sponge Cake and Its Portuguese Roots

Published October 13, 2026 at 10:25 PM JST | By Tokyo Paul

Soft, golden, and lightly sweet, castella is one of Japan's most beloved traditional sponge cakes, and its home is Nagasaki. It looks simple, yet it carries centuries of history, from Portuguese ships to the refined confectionery shops of today. A thick slice with a cup of green tea is a classic pairing, and a long box of castella makes a favorite souvenir. This guide explains where castella comes from, what makes it special, how it is eaten, and how to choose the best one on your visit to Nagasaki.

A cake that sailed from Portugal

Castella has a story that begins far from Japan. Its name likely comes from the Portuguese words Bolo de Castela, meaning "cake from Castile," and its closest relative is the Portuguese sponge cake known as pao de lo. As described in the English Wikipedia article on castella, Portuguese traders and missionaries brought such cakes to Japan in the 16th century, when Nagasaki was the only Japanese port open to foreign trade.

Nagasaki was the natural place for this to happen. The Kyushu regional tourism site explains that Portuguese ships arrived in the area in 1571 and brought European foods and customs, including bread, tempura, caramel, castella, and konpeito candy. Over time, Japanese bakers adapted the cake to local tastes, and what began as a foreign novelty became a beloved national treat.

Nagasaki and the Sugar Road

To understand why castella is so closely tied to Nagasaki, it helps to know about sugar. The Visit Kyushu article on the Sugar Road explains that sugar was largely unused in Japan before this period and changed the country's food culture. During the long period when Japan limited foreign contact, the artificial island of Dejima in Nagasaki was the main window to the outside world, and sugar unloaded there moved along a road known as the Nagasaki Kaido, or Sugar Road, toward Edo.

The same article describes the road as running about 228 kilometers from Kokura to Nagasaki, with Western-style sweets and confectionery spreading along the way and adapting to local tastes. Many sweet traditions in northern Kyushu, from yokan to marubolo cookies, are connected to this history. Castella is the most famous of them, and it remains a symbol of Nagasaki's role as a gateway for new flavors.

The article adds a charming detail about how sugar reached ordinary people. Bulk sugar imports began in 1759, and sugar that spilled during unloading, called koboremono, could be taken freely, so even people of modest means in Nagasaki got a taste. Along the road you can also find okoshi, a crisp sweet of dried rice with brown sugar and starch syrup from Isahaya, and konpeito, the sparkly sugar candy of Kitakyushu. If you enjoy castella, exploring these related sweets is a delicious way to follow the old route through northern Kyushu.

What makes castella special

Castella is made from just a handful of ingredients: flour, sugar, eggs, and mizuame, a mild starch syrup. Wikipedia notes that the syrup was added to make the cake moister, and that Japanese castella tends to be sweet and moist with a brioche-like texture. The batter is baked in a rectangular mold, and many cakes have a crunchy layer of coarse zarame sugar at the bottom, a small pleasure that many people save for the last bite.

The finished cake is sold in long boxes and cut into thick slices at home. Its flavor is gently sweet and eggy, and it pairs especially well with green tea. Variants exist as well, including matcha, honey, brown sugar, and chocolate versions. Because castella is made with eggs and wheat, anyone with allergies should check the ingredient list on the packaging carefully.

Famous makers and long histories

Nagasaki is home to some of Japan's oldest confectionery houses. Castella Honke Fukusaya, which was established in 1624, says on its official English site that its founder learned castella making from a Portuguese visitor and that the shop has been making the cake for over 390 years. The page also mentions that the shop appeared in an 1885 publication as located in the Funadaiku-machi area of Nagasaki, and that it makes its cakes without preservatives. The site also explains the shop's bat logo, a lucky symbol in China whose sound matches "fuku" in the shop's name, adopted in the hope that castella would become one of Nagasaki's most famous cakes.

Other long-established makers are also recognized in Nagasaki, including Shoken, founded in 1681, according to Wikipedia. Each maker has its own style, with differences in moistness, sweetness, and texture, so tasting several is part of the fun. If you have time, visit a few shops and compare. Many offer small sample portions or cut-and-pack options, though availability depends on the store.

How to enjoy castella

The classic way is simplicity itself. Slice a thick piece, pour a cup of green tea, and enjoy it as an afternoon snack. Because castella is so soft, a gentle hand with the knife helps keep the slices neat, and a sharp, thin blade works best.

It also appears in modern forms. Flavored versions such as matcha, honey, brown sugar, and chocolate show how a traditional recipe can be reimagined, and they are fun to compare side by side. Whichever you choose, savor the texture and the sweet, eggy aroma.

Buying castella as a souvenir

Castella is a wonderful omiyage, the Japanese custom of bringing back local food gifts. It arrives in sturdy boxes that travel well, and its simple flavor appeals to a wide range of people. Look in Nagasaki's shopping streets, near the station, and in the long-established shops themselves, where staff can help you choose a size.

A few practical tips: check the best-before date on the package, keep the cake away from heat, and carry it carefully so the box does not get crushed. Fresh castella is meant to be eaten within a limited time, so buy according to when you will share it. If you are traveling internationally, check any import rules for food products. And as with all baked goods, check for allergens before giving it to others.

Quick takeaways

Castella is a moist, golden sponge cake with Portuguese roots that became a Nagasaki specialty. Its main ingredients are flour, sugar, eggs, and starch syrup, and it is often topped by a crunchy layer of zarame sugar on the bottom. Historic shops like Fukusaya, founded in 1624, show how deeply it is woven into the city's culture. Enjoy it with green tea, try flavors like matcha or honey, and bring a box home as a gift.

When you visit Nagasaki, take a moment to appreciate how a cake from distant ships became part of everyday Japanese life. It is a sweet reminder of the city's long history as a meeting place of cultures, and it tastes wonderful too.