In Russia and China, it breeds in grass, reed, and sedge marshes. In winter and on passage, it occurs in wetlands, including tidal flats, saltmarshes, rivers, wet grassland, saltpans and aquaculture ponds and in artificial feeding grounds (in Japan). Tidal mudflat crab Helice tientsinensis has been found to be an important food source during migration, alongside smaller numbers of  other crab species (Eriocheir sinensis, Macrophthalmus dilatatum), fish and ragworms Hediste diversicolor (Li et al. 2014). It also feeds on croplands, where it is vulnerable to poisons (Y. Momose in litt. 2016). Level of human disturbance and flock size has been found to influence time spent being vigilant by this species wintering in the Yancheng Biosphere Reserve, China (Wang et al. 2011). Landscape and plot level factors are important in explaining crane occurrence, including presence of seepweed tide flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands. In the Yellow River Delta Nature Reserve, China, the species was negatively associated with roads (Cao et al. 2015).

Grus japonensis breeds in south-eastern Russia, north-east China, Mongolia (where it was first recorded in 2003 [O. Goroshko in litt. 2003]), and eastern Hokkaido, Japan (BirdLife International 2001).  The global population is split into continental and island groups, and the continental is split into birds using the eastern flyway and those using the western flyway. The eastern population is stable or slightly increasing, whilst the western flyway is severely declining (Su and Zou 2012). The Russian and Chinese populations mainly winter in the Yellow river delta and the coast of Jiangsu province, China, and the Demilitarised Zone, Democratic People's Republic of Korea/Republic of Korea, although none are thought to have been regularly wintering in DPR Korea for at least 8 years (Momose and Momose 2019). Important staging areas include the Liao River Estuary National Nature Reserve (NNR) and the Yellow River Delta NNR (Momose and Momose 2019). The Japanese population is non-migratory and was confined to Hokkaido, but has been expanding its range as numbers have increased: a pair wintered on Kunashiri Island for the first time in 2015-16 (Momose and Momose 2019).

For the continental population there is evidence of increasing concentration of birds at fewer suitable sites in both breeding areas and in wintering sites (Jiang et al. 2012, Wang et al. 2020). Breeding census data in the Sanjiang Plain shows numbers to be stable between 1984 and 2008, but with increased concentration to fewer localities due to land use changes (Jiang et al. 2012). Elsewhere the species no longer breeds at Keerqin, Xianghai and Momoge NNRs in China (Momose and Momose 2019), while in Russia there is concern that there is now insufficient habitat for the species to adjust to medium-term cyclic rainfall patterns (Momose and Momose 2019). For wintering birds, in Jiangsu only 6–7 sites out of 28 previously occupied sites were occupied in 2008, estimated to represent only 8% of the occupied range in the 1980s (Su and Zhou 2012).

The resident population in Japan has increased to c.1,900 birds (Red-crowned Crane Conservancy 2021), but this growth is not expected to continue due to habitat limitations and change in winter feeding methods by the Ministry of the Environment, Japan, to reduce high concentrations of cranes.

Conservation Actions Underway
CITES Appendix I and II.  CMS Appendix I and II.  Part of the European Endangered [Species] Programme of the European Association of Zoos and Aquaria.  It is legally protected in all range states. Key protected areas include Khingansky, Muraviovka and Lake Khanka (Russia), Zhalong, Xianghai, Hui River, Shuangtai Hekou, Yellow River delta and Yancheng (China), Kumya and Mundok (DPR Korea), Kushiro, Akkeshi-Bekanbeushi and Kiritappu (Japan). All cranes surveyed in the Sanjiang Plain region by Jiang et al. (2012) were recorded within one of seven National Nature Reserves, which collectively cover 6,994 km². Surveys of the wintering population in China have been carried out since 2006 (Su Liying et al. 2008, International Red-crowned Crane Network, unpublished data). The International Red-crowned Crane Network (IRCN) was established in the fall of 2009 following three years of discussion at international meetings hosted by the then Tancho Protection Group, now the Red-crowned Crane Conservancy. Artificial feeding has been set up at some sites (Wang Qi-shan 2008).

Conservation Actions Proposed
Identify breeding times during which particularly stringent protection rules should be implemented, as has been done at Liaoning Shuangtai Estuary (Zou Hong-fei et al. 2008). Improve general monitoring procedure, with complete censuses, satellite tracking and aerial counts. Determine Area of Occupancy to a more accurate level. Initiate a study of heavy metal contamination on the mainland (J. Harris in litt. 2009). Expand the area/number of wintering sites in Japan. Establish a transboundary protected area at Tumen estuary, between Russia/China/North Korea. Secure the conservation status of the Cholwon and Han estuary in the Demilitarised Zone. Strengthen management of protected areas on the Sanjiang plain (China), reducing human disturbance. Halt tidal-flat reclamation along the Yancheng coast (China), and control the highly invasive cordgrass Spartina alterniflora. Improve management of wetland restoration at Zhalong, to prevent floods from causing breeding failure (Wang and Li 2008). Prevent poisoning from pesticides and poaching. Control fires in the breeding grounds. Establish interest groups and a communications organisation for crane conservation in China (Wang Qi-shan 2008) and extend captive breeding programmes for future reintroduction and population supplementation.