  To evaluate different technologies for calorimetry at the International
Linear Collider, the CALICE collaboration has constructed a highly granular
analog hadron calorimeter with small scintillator cells, individually read out
by silicon photomultipliers. This device has been extensively tested in
particle beams. A digital hadron calorimeter based on RPC readout is currently
under construction, with first prototype beam test results already available.
The high granularity allows detailed investigations of the substructure of
hadronic showers, and can also be exploited for the development of
sophisticated reconstruction algorithms.
