Herbs (0.2-)0.5-2 m tall, biennial. Stem solitary, 3-10 mm in diam., erect, much branched. Lower stem leaves petiolate; leaf blade elliptic to narrowly ovate-elliptic, 7-30 × 3.5-9 cm, pinnately lobed, both surfaces green, scabrous, and gland-dotted; lateral lobes 5-8 pairs, obliquely triangular to linear-oblong, margin usually entire, apex obtuse; terminal lobe narrowly ovate-elliptic to linear. Middle and upper stem leaves shortly petiolate or sessile, gradually smaller upward on stem, pinnately lobed or undivided. Capitula very numerous, in a corymbiform or paniculiform synflorescence, shortly pedunculate. Involucre narrowly campanulate, 5-8(-10) mm in diam. Phyllaries in 5 or 6 rows, green with a dark purple midvein, arachnoid to glabrescent, gland-dotted, apical appendage purple, orbicular, 1-2 mm wide, and membranous; outer phyllaries ovate to narrowly triangular-ovate, 2-3 × 1-1.5 mm, apex acute or with a small appendage; middle and inner phyllaries narrowly elliptic to linear, 4-10 × 0.8-1.5 mm, apex with a larger appendage. Receptacle bristles 5-6 mm. Corolla purple, 1-1.4 cm, gland-dotted, tube 6-8 mm, limb 4-6 mm, lobes 4-5 mm. Achene straw-colored with dark spots, cylindric to obconic, 3-4 mm. Pappus dirty white; outer bristles ca. 2 mm; inner bristles 7-9 mm. Fl. and fr. Jun-Nov. 2n = 26, 28.

Saussurea japonica has often been confused with S. amara (e.g., S. W. Liu, Fl. Yunnan. 13: 538. 2004), mainly because many herbarium specimens lack underground and basal parts. Saussurea amara is a perennial species with undivided basal leaves of steppe and often saline and alkaline soils in N and W parts of the country, whereas S. japonica is a very widespread tall biennial plant with pinnatifid to pinnatisect basal leaves in a variety of habitats but usually not on saline soils. Saussurea japonica seems to be absent from Xinjiang and Xizang. Plants in the SE part of the country tend to have smaller capitula (matching S. microcephala) and may deserve separate taxonomic status.

Mountain slopes, forests, thickets, loess slopes, roadsides, wastelands, fallow fields; 200-2900 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Korea, Mongolia].