Board Thread:General Discussion/@comment-10786787-20130613005503/@comment-5693502-20140610222844

Stefan (Shikai - "Rust & Shatter") wrote: Does is focus the Reiatsu like light through a lens, or is more like the effect oxygen has on fire? I quite like those analogies. Based on them I'd say, for the vast majority of shikai (and definitely bankai), it boosts their reiatsu like the effect of more oxygen to fire. However by the same token, Ichigo's former bankai Tensa Zangetsu seems like it boosted his reiatsu by focusing it like light through a lens (i.e. compressed bankai).