C. japonica is highly migratory, occupying open habitats, including rolling grasslands, cultivated fields, steppes, montane foothills, and forest clearings (Madge and McGowan 2002, McGowan and Kirwan 2020), found to 1,000m in Japan (Chikara 2019). Habits largely expected to be similar to C. coturnix, preferring dry riverine meadows, but thought to be more tolerant of damp meadows (Madge and McGowan 2002, McGowan and Kirwan 2020).

C. japonica may be found during the breeding season in eastern Asia, from northern Mongolia east through the Baikal and Vitim regions, and the Sakhalin Islands of Russia, continuing south-east into the Hokkaidō, Tōhoku, Kantō, and Chūbu regions of Japan, as well north-east China, and North Korea (Madge and McGowan 2002, Chikara 2019, McGowan and Kirwan 2020, eBird 2024). The species undertakes migration during the winter, with many remaining in Japan but it is also found further south in Kantō, Chūbu, as well as Kansai, Chūgoku, Shikok, and Kyūshū and Okinawa (Madge and McGowan 2002, eBird 2024). Outside of Japan, wintering birds move south into central and southern China including Hainan and Taiwan, China (Williams et al. 1992, Melville and Li 1998, eBird 2024), further into north-west Myanmar, northern Thailand, Viet Nam, and Lao PDR (Madge and McGowan 2002, Chikara 2019, McGowan and Kirwan 2020, eBird 2024).

The species was previously thought to have a small resident population in Bhutan, but breeding is unconfirmed (Rasmussen and Anderton 2005) and with no recent records of the species in Bhutan (eBird 2024), these records are considered to have been vagrants, or belonging to C. coturnix. Additional vagrant records have been recorded in north-east India, Cambodia, Philippines, and Malaysia (McGowan and Kirwan 2020, eBird 2024). There are further resident, introduced populations in Italy, Reunion, and the Hawaiian Islands, USA (Madge and McGowan 2002, Chikara 2019, Madge and Kirwan 2020). As a popular farm-bred species for hunting, consumption, or display purposes, escapees may be reported from Europe, Singapore, USA, and east coast Australia (eBird 2024).

Conservation Actions Underway
The species has been removed from the list of game birds in Japan as of 2013 (Natural Environment Bureau, Ministry of the Environment in Shimomura and Hadano 2022). The species is systematically surveyed as part of the Japan Breeding Atlas Program. 

Conservation Actions Proposed
Targeted surveys across the species' range are required to determine an accurate global population size, including in areas where the species' status is uncertain (i.e., north-east India and Bhutan). Research is required to determine the severity of threats (i.e., hunting, habitat loss, climate change). Monitoring is required to determine the population trends over time, and in response to threats.