From:
https://en.wikipedia.org/wiki/Buyan-class_corvette
The Buyan-class corvette was designed by Zelenodolsk Design and designated Project 21630 by the Russian Government. This is one of the newest corvettes of the Russian Navy. The first ship of her class, Astrakhan, was commissioned in September 2006, and assigned to the Caspian Flotilla.
In August 2010 some information about newly modified Project 21631 ships was published. The lead ship of this project, Grad Sviyazhsk, was laid down on 27 August 2010. This ship is a missile version of Project 21630 "Buyan" small-size gunnery ship and is dubbed as "Buyan-M". This ship of Project 21631 is dedicated to the defense of national economic zones and its main purpose is engagement of surface warships. This is going to be an up-to-date ship armed with missile and artillery weapons, and equipped with electronic countermeasure equipment. The yard will build five ships including the lead one, since a contract was approved by the Russian defense ministry on 26 May 2010
