The parameters of the JLC detector have not been changed since the green book (1992). The primary goals are: (1) hermetic calorimetry covering 0.98 located inside the magnet coil of a 2Tesla solenoidal field; (2) high-precision tracking to reconstruct the recoil mass of a light Higgs boson with a resolution of 200MeV in the process ; and (3) good vertexing to detect b-quarks in many types of background. The technique has been chosen to be conventional so that the scale of the JLC detector is large, as shown in Fig.13.
Figure 13: Schematic view of the JLC detector. The total volume and weight are m and 15,000 ton, respectively.
Recently, a European group proposed the "1 TeV detector"  as a high-performance detector, which is very similar to the JLC. A detector with a higher magnetic field (4 Tesla) has been suggested to optimize the performance of vertexing (next section) by C.Damerell at a previous workshop. Such an alternative detector will also be considered seriously.