Lǐ Dēng 李登 (fl. mid-third century), a Three Kingdoms 三國魏 phonologist. Suí shū jīngjí zhì 隋書‧經籍志 records his Shēng lèi 聲類 (KR1j0110) in ten juàn — the earliest documented Chinese rhyme dictionary, predating the Qièyùn 切韻 (601) of Lù Fǎyán 陸法言 by some three-and-a-half centuries and the Yùn jí 韻集 (KR1j0111) of 呂靜 Lǚ Jìng by a generation. Lǐ Dēng’s Shēng lèi originated the systematic five-tone (wǔ shēng 五聲) classification of Chinese syllables that the later Qièyùn tradition would refine into the four-tone píng-shǎng-qù-rù 平上去入 system. The work was lost in the late Táng or Sòng but survives in fragments preserved chiefly in Jīngdiǎn shìwén and Buddhist yīnyì; reconstructed in CHANT. No biography in any standard history; he is sometimes placed at the Wèi court under Wéi Yáo’s 韋曜 generation but no firm identification. CBDB has no matching entry.