If the principal chord (X) is partially replaced by the subsidiary (Y), there are three possible positions - beginning, middle, and end - for the subsidiary:
For example, a subsidiary chord in a modulation.
A subsidiary chord may be a chord with related function and/or sharing pitches, for example in E major, C♯m (C♯-E-G♯) as a subsidiary for E (E-G♯-B), which share two of three pitches and are related as tonic parallel (vi) and tonic (I).
See also 
Further reading 
- Van der Merwe (2005), p. 428.
- Van der Merwe, Peter (2005). Roots of the Classical: The Popular Origins of Western Music, p.501. ISBN 0-19-816647-8.
- Becker, Julius (1845). A concise treatise on harmony, p.17. Ewer & Co.