We study composition-valued continuous-time Markov chains that appear naturally in the framework of Chinese Restaurant Processes (CRPs). As time evolves, new customers arrive (up-step) and existing customers leave (down-step) at suitable rates derived from the ordered CRP of Pitman and Winkel (2009). We relate such up-down CRPs to the splitting trees of Lambert (2010) inducing spectrally positive L{e}vy processes. Conversely, we develop theorems of Ray-Knight type to recover more general up-down CRPs from the heights of L{e}vy processes with jumps marked by integer-valued paths. We further establish limit theorems for the L{e}vy process and the integer-valued paths to connect to work by Forman et al. (2018+) on interval partition diffusions and hence to some long-standing conjectures.
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