Twelve eight-car 10-300 series sets (96 vehicles) were built between 2004 and 2006 to replace the older (1st and 2nd batch) 10-000 series sets dating from the late 1970s.
These were designed to be lengthened to ten-car sets in the future with the insertion of additional motored and trailer cars as cars 3 and 4.
The majority of the sets were built by Tokyu Car Corporation (now J-TREC) in Yokohama, but the intermediate cars of the three sets 10-450 to 10-470 were built at JR East's Niitsu factory in  Niigata Prefecture, and these were transferred to Tokyu Car's Yokohama factory in two batches in January and February 2006 to be incorporated into the completed sets.
The first set, 10-370, was delivered in November 2004 for night-time testing of the new D-ATC signalling system.
The first sets entered revenue service on 21 May 2005.

The six eight-car 10-300R series sets were created in 2005 and 2006 by adding new 10-300 series driving cars built by Tokyu Car sandwiching three pairs of refurbished 10-xx7 and 10-xx8 cars from former 10-000 series sets 10-010 to 10-180.

The newly formed ten-car sets (10-450 to 10-480) entered revenue service from 1 June 2010.
Lengthening from eight to ten cars involved inserting new 2nd-batch "10-4x3" (T1) trailer cars and "10-4x5" (M1) motored cars, and renumbering the original "10-4x5" cars to "10-4x4" as well as removing the original pantograph.

A further three new ten-car 3rd-batch sets were delivered during 2013.
The first, set 10-490, entered revenue service on 15 September 2013.
These sets are based on the JR East E233 series design.

The last remaining 10-300R series set in service, set 10-330, was withdrawn following its final run on 14 February 2017.
Twelve eight-car 10-300 series sets (96 vehicles) were built between 2004 and 2006 to replace the older (1st and 2nd batch) 10-000 series sets dating from the late 1970s. These were designed to be lengthened to ten-car sets in the future with the insertion of additional motored and trailer cars as cars 3 and 4. The majority of the sets were built by Tokyu Car Corporation (now J-TREC) in Yokohama, but the intermediate cars of the three sets 10-450 to 10-470 were built at JR East's Niitsu factory in  Niigata Prefecture, and these were transferred to Tokyu Car's Yokohama factory in two batches in January and February 2006 to be incorporated into the completed sets. The first set, 10-370, was delivered in November 2004 for night-time testing of the new D-ATC signalling system. The first sets entered revenue service on 21 May 2005.
The six eight-car 10-300R series sets were created in 2005 and 2006 by adding new 10-300 series driving cars built by Tokyu Car sandwiching three pairs of refurbished 10-xx7 and 10-xx8 cars from former 10-000 series sets 10-010 to 10-180. 
The newly formed ten-car sets (10-450 to 10-480) entered revenue service from 1 June 2010. Lengthening from eight to ten cars involved inserting new 2nd-batch "10-4x3" (T1) trailer cars and "10-4x5" (M1) motored cars, and renumbering the original "10-4x5" cars to "10-4x4" as well as removing the original pantograph.
A further three new ten-car 3rd-batch sets were delivered during 2013. The first, set 10-490, entered revenue service on 15 September 2013. These sets are based on the JR East E233 series design.
The last remaining 10-300R series set in service, set 10-330, was withdrawn following its final run on 14 February 2017.
Toei 10-300 series