Variation
Buxus microphylla var. koreana                  Korean Box 
This dwarf shrub grows to 600mm (2ft) tall and has a spreading habit. The bronzes tinted leaves are up to 16mm (¾in) by 12mm (½in) wide and are obovate to elliptic. They may be notched, blunt or pointed at the apex and the plant grows in an open sunny position.

Cultivars
Some of the following cultivars may only be found in New Zealand, USA or Great Britain.

'Sunnyside'
This hardy plant has pale green foliage that becomes bronze during the winter.

'Tall Boy'
This plant has an upright habit and grows to 1.2m (4ft) high by 1.5m (5ft) wide.  The green foliage turns brown in winter.

'Tide Hill'
This evergreen plant has lustrous foliage and grows 330mm (15in) by 1.5m (5ft).

'Winter Beauty'
This plant has deep green leaves and grows to 1m (3ft) by 1.2m (4ft).

'Winter Gem'
This plant grows to 700mm (2ft) high with downy foliage.

'Winter Green'
This cold hardy plant has small light-green foliage and grows 1.5m (5ft) high and wide.

var. koreana x B. sempervirens hybrids

Chicagoland Green®
This vigorous, cold hardy plant grows to 1m (3ft) high.

'Green Gem'
This plant has a spherical habit and requires minimal pruning.  It has dark green leaves and grows to 600mm (2ft) high.

'Green Ice'
This extremely cold hardy evergreen has lustrous foliage. 

'Green Mountain'
This upright plant forms a wide conical shape.  The foliage is deep green and it grows 1.5m (5ft) high and 1m (3ft) wide.

'Green Mound'
This plant has deep green leaves and a bun shaped habit.

'Green Velvet'
This slow growing evergreen grows 1.2m (4ft) by 1.2m (4ft).

Variation
B. microphylla var. japonica              Japanese box           
The leaves are obovate to obcordate, with the apex pointed or notched. They are up to 20mm (¾in) long and up to 8mm (⅛in) wide. This is a slow growing and compact plant.
‘Buxus’: box - the ancient Latin name for this plant; ‘microphylla’: small leaves; ‘japonica’: of Japan. 

Cultivars
'Kingsville Dwarf' (var. japonica form)
This slow growing plant has tiny leaves and is often used for bonsai.

var. koreana Nak.
This plant is exceptionally cold hardy with pubescent new growth and yellowish foliage.  The habit is not dense.

'Morris Midget'
This plant has yellow-green foliage and a low bun shaped habit.

'National'
This plant has glossy green leaves and an upright habit.  It grows 5m (15ft) high and wide.

'Pincushion'
This hardy plant has pale green foliage that becomes bronze during the winter.  It has a low bun shaped habit, growing 500mm (1½ft) high by 600mm (2ft) wide.

'Richardii'
This vigorous plant has large deep green leaves.