Radical 134 or radical mortar (臼部) meaning "mortar" or "joint" is one of the 29 Kangxi radicals (214 radicals in total) composed of 6 strokes.

In the Kangxi Dictionary, there are 71 characters (out of 49,030) to be found under this radical.

臼 is also the 136th indexing component in the Table of Indexing Chinese Character Components predominantly adopted by Simplified Chinese dictionaries published in mainland China, with 𦥑 being its associated indexing component.

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  Small seal script character

• Fazzioli, Edoardo (1987). Chinese calligraphy : from pictograph to ideogram : the history of 214 essential Chinese/Japanese characters. calligraphy by Rebecca Hon Ko. New York: Abbeville Press. ISBN 0-89659-774-1.
• Lunde, Ken (Jan 5, 2009). "Appendix J: Japanese Character Sets" (PDF). CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing (Second ed.). Sebastopol, Calif.: O'Reilly Media. ISBN 978-0-596-51447-1.

• Unihan Database - U+81FC