The Serpentine Gallery has announced that its 2009 pavilion will be designed by architects Kazuyo Sejima and Ryue Nishizawa, of the leading Japanese practice SANAA. Sejima and Nishizawa’s pavilion will be the architects’ first built structure in the UK and the ninth commission in the gallery’s annual series of pavilions. It will open in July on the Serpentine Gallery’s lawn, where it will remain until October. SANAA’s clients range from the Louvre Museum in Lens, France to the New Museum of Contemporary Art in New York. There is no budget for the Serpentine Gallery Pavilion commission. It is paid for by sponsorship, sponsorship help-in-kind, and the sale of the finished structure, which does not cover more than 40 percent of its cost.