 For more than 200 years, the island nation of Japan was largely self-isolated, foreign travel was banned, and international trade was severely limited. That all changed in the 1800s when Japan changed its policies and suddenly found itself in need of ships suitable for international voyages. Following the opening of Japan, a rapid modernization effort began within Japanese industries, including shipbuilding and repair. One of the first challenges was to find a location for a shipyard. Shipbuilding began to search for an area near the capital of Tokyo that would serve as the headquarters of their new domestic shipping enterprise. Ultimately, Yakosuka was chosen since it would be able to serve as a defensive barrier to the entrance of Tokyo Bay and it possessed the necessary depth for larger ships. Construction on Dry Dock 1 began on November 15, 1865. The massive construction project required thousands of stone blocks which were carved by hand out of the local mountains and brought to the Bay of Yakosuka. After several years of construction and overcoming challenges, the ambitious project was complete and Dry Dock 1 officially opened on February 8, 1871. Eventually Dry Dock 1 was enlarged to accommodate newer and larger ships. Modern concrete construction techniques were used, resulting in the contrasting walls seen today. To a complex operation, the basic steps of the Dry Dock allow it to be flooded so a ship or vessel can enter safely. Then it is closed off and the water pumped out, leaving the hull accessible for upgrades and repair. The process is then reversed for the ship to head back to sea. Dry Dock 1 in Yakosuka, Japan continues to serve ships to this day and is one of the oldest Dry Docks in the world still in operation. In just 75 years, Japan transformed from a secluded island nation to having one of the largest naval forces in history. Commander Fleet Activity Yakosuka is the most significant location in Japan where this transformation took place, and the historical Dry Docks from that time period are still being used. Here, you can witness the development of engineering and technology from the 1870s to the 1940s as seen in Dry Docks 1 through 6. Dry Docks are vital to the construction, repair, and maintenance of sea-going vessels. Japan constructed their first large ship Dry Dock, Dry Dock 1, in Yakosuka in 1871 and over the next seven decades completed five more Dry Docks, all of which are still in use today. Dry Dock 2 opened in 1884 and was the largest Dry Dock in all of Asia at the time at 170 yards long. Dry Dock 3 was finished three years after Dry Dock 1 in 1874. Dry Dock 4 was completed in 1905 just as Japan was asserting its naval power throughout the region. That same year, Japan defeated Imperial Russia in the short but intense Russo-Japanese War. Dry Dock 4 was the first Dry Dock built using concrete and stonework, and was the first designed entirely by a Japanese engineering team. Dry Dock 5, completed in 1916, dwarfed the size of earlier Dry Docks to accommodate the size of ships being built during that time. The final and largest Dry Dock to be built in Yakosuka was Dry Dock 6, completed in 1940, and is more than three football fields long. Dry Dock 6 was the construction site for the Japanese aircraft carrier, Shinano. By the time Shinano was completed, it was the largest aircraft carrier the world had ever seen.