The low temperature phase of the spin-1/2 nearest neighbour antiferromagnet
on the Kagome lattice has been under debate for several years. We present
results from our ongoing effort to investigate this problem using
contractor renormalisation (CORE). We construct the effective Hamiltonian
using a building block of 12 spin-1/2 sites, improving upon earlier
attempts with 3 sites. Preliminary results till range-3 will be discussed.
A general technique ([1]) based on singular value decomposition which enables
us to accomplish these calculations with very modest computational
resources will be described.

1. M. Weinstein, A. Auerbach, and V. R. Chandra, Phys. Rev. E, 84, 056701 (2011)