Invisible in their omnipresence, these humble concrete blocks speak volumes about the indelible forces that have shaped two island communities on opposite sides of the Pacific.
Clockwise from top right: Okinawa Nursing Training Center and Okinawa Dental Office, both located in the town of Haebaru; Care House Tinsagunu Hana, located in Naha.
Enabled by advancements in concrete fabrication and rises in the costs of labor and traditional building materials like stone and wood, the decorative concrete blocks were a cost-effective way to screen buildings from excessive sun while also encouraging natural ventilation, making them particularly popular in places with hot and humid climates, like Hong Kong, Honolulu, and Naha.Hana blocks have the added advantage of high thermal mass, meaning they absorb the sun’s heat during the day and release it at night, making them well-suited to desert locales like Palm Springs. Like Islamic mashrabiya, they are an example of geographically influenced, climate-responsive architecture—a chunkier, more modern version of European brise-soleil or Indian jali.Throughout the 1950s, ’60s, and ’70s, the world saw a proliferation of decorative concrete block screens. In Honolulu, this coincided with the middle of a post-Statehood building boom. “There are a lot of cookie-cutter, planta- tion-type homes,” says Honolulu architect Jason Selley. “A home’s breezeblock pattern was the “one area where archi- tects could flex some creativity within a standard module.”In Okinawa, concrete construction exploded in the years after World War II, during which an estimated 100,000 homes were destroyed. Out of this architectural evolution came the now ubiquitous hana block, driven both by the rising cost of traditional building materials and the arrival of U.S. military construction technology. As in Hawai‘i, hana blocks were ornamental but also highly functional, respon- sive to the island’s subtropical climate and resistant to threats like typhoons and termites.They were also cheap to produce. Thousands of blocks could be made with a single mold. Concrete masonry companies, which emerged as U.S. military bases were established throughout Okinawa after the war, began offering standard shapes and patterns that architects could select from catalogs.
Hana blocks invited architects like Nakaza to play. A single block could be flipped around or turned upside down to create new patterns. It was a totally new way to decorate façades, and yet there was something timeless about it, almost reminiscent of those early childhood rites of passage of making shapes and stacking blocks.
While today flower blocks are part of the essential “Okinawaness” of the prefecture’s architectural fabric, it took
time for the decorative concrete element to be accepted by the public. As the scholar Naoki Isobe has pointed out, hana blocks were originally referred to as “irregular blocks” and were perhaps negatively associated with stone construction, at the time limited to sheds and outbuildings. Isobe has the- orized that flower blocks—and the evolution of their name— may have played a role in loosening the public’s “rejection of stone construction,” laying the groundwork for the concrete architectural renaissance that was to come.
At its best, architecture tells us where we are. It is a record of how previous generations lived, what they valued, and why. For those living among the hana blocks of Okinawa and their counterparts across the globe, they are often sim- ply a backdrop, invisible in their omnipresence. But hidden in the many forms of this humble detail is a recognition that how we build can—and should—respond to the world around us. As with so many objects, these simple blocks hold the stories and histories, preoccupations and aspira- tions, of those who came before us.
