This stamp reveals a tricky area of taxonomy. In Howard & Moore (1980), Otus bakkamoena lempiji is listed as occuring in Java, Bali and Borneo. The Owl Pages lists Otus lempiji as Sunda Scops Owl (formerly grouped with Collared Scops), and Otus lettia as Collared Scops Owl. This is probably the latest situation, and I suspect the species shown on this stamp is intended to be Collared Scops Owl.

There is a distant photograph of this species at a nest box on the Japanese site of Hiroaki Sakagawa.  It is interesting to note that the scientific name given on that site is the same as on the stamp.

Extract from "Birds of Japan"
COLLARED SCOPS OWL Otus bakkamoena <0-konoha-zuku> L 24cm. Resembles Scops Owl but is slightly larger; has a grayish collar on the nape: orange eyes: feathered toes. Voice: Weak cat-like mew. Status: Uncommon resident throughout Japan. Breeds in mountain forests (also lowlands in north) and winters in warmer areas. Sometimes occurs in woods near human habitation.

Extract from "Owls of the World"
SCOPS OWLS

In the Old World the scops owls have evolved along similar lines as the American screech owls, to fill similar ecological niches in both forest and open country. Geographical and climatic
changes have left isolated species with restricted distributions over Africa and the Orient. They
are the remnants of once more widely spread populations and their affinities are obscure.
Many of the species live on the oceanic islands off oriental Asia where populations have been
isolated and developed into many different species and subspecies. The taxonomic situation is
complicated by the lack of knowledge about some species. For a few, neither breeding season,
food nor even voice are known.

The greatest ecological differentiation is seen in South-east Asia where the ranges of the collared (0. bakkamoena), reddish (0. rufoscens) and spotted  (0. spilocephalus) scops owls overlap. The  collared scops owl, which has only very minor morphal differences in shades of brown rather than grey and rufous phases, ranges from Pakistan and India across to southern China and Japan and down to Malaysia and the Philippines. Its habitat is open country, including towns and gardens. It is probable that its natural habitat in South-east Asia is the open savannah-like grassland and mangrove swamps of the coasts. In the forests of Malaysia the collared scops owl is replaced by the forest-dwelling reddish scops owl and, further up in the mountains, by the spotted scops owl; but through the felling and opening of the primary forest, the collared scops owl is spreading inland at the expense of the others.

The collared scops owl nests in hollow trees, rocks, old buildings and the disused nests of other
birds. It lays four or five eggs in the north of its range where it nests in spring but lays only three
or four eggs in the south where it breeds during the period of maximum rainfall. In the northern
parts of its range, it has denser plumage on its tarsi and, in Japan and China, even the toes are
well feathered.

Unlike their New World counterparts, the common screech owls, which are split up from
north to south into six species, the collared scops owls form one huge interbreeding species from the tropical woodlands of Java to the temperate valleys of eastern Siberia. On
northern Luzon, a rather larger race, megalotis, is often regarded as a separate species.
The collared scops owl is unusual amongst owls, and other birds of prey, in that it is used
for human consumption. At one time Chinese doctors recommended owl soup for consumptive
and rheumatic patients. The collared scops owl formed the main ingredient.