The Meiji Constitution was drafted in Yokosuka

A monument commemorating the location where the Meiji Constitution was drafted exists on the western edge of Natsujima, but was originally erected on the grounds of the Yokosuka Naval Air Station.

(Info on Natsushima: Discover Yokosuka 横須賀奥旨: Search results for natsushima (deepyokosuka.blogspot.com)) 

In drafting the Imperial Constitution, Hirobumi Ito and others involved were working at an inn called Azumaya in Kanazawa. However, because the draft, which had been stored in a luggage case, was stolen, the location was moved to Hirobumi Ito's villa on Natsushima. The monument was erected at the location of the workroom in this villa.

Natsujima was later cut down to build an airfield for the naval air force during the Taisho era (1912-1926), and the surrounding area was reclaimed and connected to the land. As a result, this place became the site of the air force airfield and other facilites.

After the war, the monument was renovated in 1951, and the unveiling ceremony was held again, but later was moved again, when the site became the property of Nissan Motor Co.

The granite monument that now stands in the center of the site was newly built during the renovation in 1951, and originally consisted only of a stone slab for the foundation. This was done so as not to affect the plane's runway. Instead, a copper plate engraved with a plan of the villa was embedded in the center, but it was stolen after the war and has not survived. Incidentally, the existing inscription on the copper plate was also stolen, but was miraculously found and restored/embedded in its original position.

Meiji Constitution | 1889, Japan | Britannica

Meiji Constitution, constitution of Japan from 1889 to 1947. After the Meiji Restoration (1868), Japan’s leaders sought to create a constitution that would define Japan as a capable, modern nation deserving of Western respect while preserving their own power. The resultant document, largely the handiwork of the genro (elder statesman) Itō Hirobumi, called for a bicameral parliament (the Diet) with an elected lower house and a prime minister and cabinet appointed by the emperor. The emperor was granted supreme control of the army and navy. A privy council composed of the Meiji genro, created prior to the constitution, advised the emperor and wielded actual power. Voting restrictions, which limited the electorate to about 5 percent of the adult male population, were loosened over the next 25 years, resulting in universal male suffrage. Political parties made the most of their limited power in the 1920s, but in the 1930s the military was able to exert control without violating the constitution. After World War II, a U.S.-approved constitution stating that “sovereign power resides with the people” replaced the Meiji Constitution.