Hai Collection, Upper Volume Radical: Horse (mǎ) Entry: 騳 Kangxi strokes: 20 Page 1443, Entry 05 Jade Chapter (Yupian) records the pronunciation as du (rising tone), which is the same as the character for alone or unique. The meaning is a horse running. Six Writings Principles (Liushugu) explains it as the sound produced by two horses running together, described as du-du.