- The E231 Series 1000, introduced in 2000, served as a replacement for the 115 Series and 211 Series previously active on the Utsunomiya Line (Tohoku Line) and Takasaki Line. The formations introduced to the Oyama Rolling Stock Center in the early 2000s feature unique characteristics such as continuous green bands along the side panels, long runboards extending over the driver's door on the leading cars, a non-glass cockpit driver's console, and different toilet placements compared to those expanded for the Tokaido Line post-2004.
- Both the 10-car and 5-car formations have been updated with the latest equipment specifications for production. You can enjoy operating in a maximum configuration of 15 cars when combined with the popular E231 Series 1000 Tokaido Line (Updated Cars) and E233 Series 3000 Tokaido Line & Ueno-Tokyo Line.
- The U522 formation (10 cars) and U60 formation (5 cars) from the Oyama Rolling Stock Center have been reproduced after equipment upgrades.
- Reproduces features typical of early models, such as a body with continuous green side bands and a roof equipped with small air conditioners throughout the train.
- The leading car features a long runboard extending over the driver's door and a non-glass cockpit driver's console.
- Recreates the film applied state around the destination and train number displays on the front glass of car 15 (KUHA E231-8022).
- Newly manufactured AU725B cooler (by TORA) applied to cars 6–10 and 14–15.
- Car 10 (KUHA E231-6022) without a toilet and car 6 (SAHA E231-6022) with a toilet are reproduced.
- The 10-car set and 5-car accompanying formation set accurately recreate the updated underfloor equipment of MOHAE230/MOHAE231.
- Saro E231/E230 trucks reproduce the configuration with yaw dampers removed.
- Features a slotless motor for smooth and quiet operation.
- Affiliation markings are set as "Miya Yama," and safety device notations are represented as "P" and "SN."
- Equipped with head/tail lights and front destination display (using white LED). Cars 10 (KUHA E231-6022) and 11 (KUHA E230-6022) have a light-off switch.
- The front coupling sections of cars 1 and 15 utilize dummy couplers, while cars 10 and 11 use KATO couplers in close-coupled form (without hooks), with electric unions included.
- The intermediate coupling section is standardly equipped with body-mounted KATO close-couplers (with hooks), ensuring realistic coupling appearance and smooth operation.
- Compatible with interior lighting kit Kato 11-211 (Kato 11-212)