  We define a notion of normal form bisimilarity for the untyped call-by-value
lambda calculus extended with the delimited-control operators shift and reset.
Normal form bisimilarities are simple, easy-to-use behavioral equivalences
which relate terms without having to test them within all contexts (like
contextual equivalence), or by applying them to function arguments (like
applicative bisimilarity). We prove that the normal form bisimilarity for shift
and reset is sound but not complete w.r.t. contextual equivalence and we define
up-to techniques that aim at simplifying bisimulation proofs. Finally, we
illustrate the simplicity of the techniques we develop by proving several
equivalences on terms.
