The Chong-ak variety in the local Kalinga language is called 'Unoy' or 'Uloy', the broad linguistic term for this type of medium grain staple rice. In the province of Ifugao (local languages Ifugao and regional language Ilokano) the broad linguistic term for the subspecies tropical japonica is 'Tinawon', meaning 'once a year'. The specific variety of this nomination is called 'chong-ak' in the Kalinga language of the municipality of Pasil, Kalinga. Pasil and the adjacent valleys located in the municipality of Lubuagan are the main production areas for the exported rice, but this variety is found throughout the three-province project area. The local name varies among the isolated villages, as the dialects between mountain villages are quite different and the languages of the different ethno-linguist groups (Kalingas, Ifugaos, Bontoc and Kankanay) are completely separate. The plump, rust red, seed-coated variety is known in nearby municipalities as: 'dumalingan' in the municipality of Tanudan, Kalinga; ' chumalingan' in the municipality of Lubuagan, Kalinga; 'phaflar' in the municipality of Mayoyao, Ifugao; 'chum-e' in municipality of Asipulo, Ifugao; and 'gomiki' or 'ginulot' in Sadanga, Mount Province.
Based on morphology, Chong-ak belongs to the rice genus Oryza sativa, race tropical japonica (also known as javanica). It is a slow-growing staple variety that requires a 5-6 month growth period from transplanting to harvest. It is planted from December through February and harvested from the middle of June through August, depending on the elevation. The variety grows best in irrigated terraces at elevations between 500 and 1500 meters above sea level. The plant is tall (120cm-150cm), cold tolerant, non-shattering, aromatic, but low tillering (4-6 tillers/hill). It is a traditional native variety that has never undergone improvement in a formal breeding program or at research institutes. The indigenous women of the area are the primary holders of the traditional knowledge on seed selection and conservation of the best planting seeds. Chong-ak is a described as a true medium-sized grain with a rust red seed coat. Research on tropical japonica/javanica rice by the International Rice Research Institute (IRRI) states that this subspecies has been found in only three places in the world: remote areas of Indonesia, the rice terraces of the Philippines, and in the mountainous areas of Madagascar. Until recently, these treasured aromatic varieties were rarely sold into the commercial market.
Chonk-ak has historically been grown in the high-elevation, irrigated rice terraces of Northern Luzon's (Philippines) Central Cordillera Mountains, specifically in the municipalities of Pasil and Lubuagan, in the Province of Kalinga, but locally adapted similar varieties are grown in the adjacent mountain valleys of Mountain Province and Ifugao Province. The rice remains the preferred staple variety of indigenous people in the areas where it is grown.
The Chong-ak variety is intimately connected to the indigenous Taguibong people of Kalinga and their cultural practices. Chong-ak would be served during weddings and family reunions, especially during the Pusipus celebration, the gathering of relatives before a sick or elderly family member dies. Bundles of Chong-ak palay (unthreshed rice on its panicle sheath) are displayed at the feet of the dead to symbolize his or her wealth in rice fields and harvest.