  We reconstruct non-trivial 6d theories obtained by Blum and Intriligator by
considering IIB or SO(32) 5 branes at ALE spaces in the language of Hanany
Witten setups. Using ST duality we make the equivalence of the two approaches
manifest, thereby uncovering several new T-duality relations between the group
theoretic data describing the embedding of the instantonic 5 brane in the ALE
and brane positions in the Hanany Witten language. We construct several new 6d
theories, which can be understood as arising on 5 branes in IIB orientifolds
with oppositely charged orientifold planes recently introduced by Witten.
