A Japanese investor has made a splash with its first D.C. purchase, acquiring a Mount Vernon Triangle office building in the District's largest property sale of the year so far.

An affiliate of Tokyo-based Mori Trust Co. acquired the office building at 601 Massachusetts Ave. NW for $531M from Boston Properties, the Washington Business Journal reports.

The sale tops the previous high-water mark for most expensive in D.C. this year, besting Nuveen Real Estate's $375M acquisition of an office at 601 D St. NW from Tishman Speyer.

The office building is anchored by Arnold & Porter, which agreed to pre-lease a large chunk of the 460K SF property for its headquarters in 2013. The site was long the home of National Public Radio before it relocated to NoMa. The development was built in less than three years and cost $350M.

This is Mori's first acquisition in D.C. proper, but it has been active in the suburbs; an affiliate bought two Herndon office buildings in March for $142M from Barings.

Mori has been looking to invest about $1.43B in real estate outside of Japan since 2016, according to WBJ. Previously, the firm has acquired office properties in Boston and Silicon Valley.

Mori isn’t the first Japanese investor to make a splash in the D.C. office market.

From 2016 to 2017, Tokyo-based Unizo Holding Co. was the dominant buyer of District office buildings, spending at least $1.2B. For a period, it was responsible for more than a quarter of all office sales volume in the District.

Its portfolio rapidly grew to include more than 2M SF, but its presence in the city burned bright and faded away. The firm sold three of its D.C. assets — all for less than it paid — before agreeing to be acquired by a coalition of its own employees and Dallas-based Lone Star Funds.

Other Japanese investors have had more success: North American Sekisui House is the primary backer of the mixed-use City Ridge, the Wegmans-anchored redevelopment of the Fannie Mae headquarters near Tenleytown that celebrated its grand opening in July.