Through esoteric rituals, it may be possible for a being to exist in two places at once. The Treachery of Maps may additionally blur the definition of the word "here". This anomaly may also affect the more chaotic and sunless regions of the High Wilderness, such as the Reach. For example, a zee-captain may find Demeaux Island to the north-east of London, while another will report it due East. This Treachery can also cause seemingly immobile objects, such as ports or islands, to inexplicably drift in location. It can be extremely difficult to assemble a map of the Neath sensibly, assuming they make any sense in the first place. The Treachery of Maps is responsible for the unreliability of maps in the Neath.
"Maps in the Neath are treacherous – maps of the Zee, doubly so." These Treacheries are a result of the strong concentration of irrigo within the Cave of the Nadir, which prevents the Judgements from seeing within the Neath, keeping the Echo Bazaar's activities hidden from their sight. The Neath is protected by seven Treacheries, four of which are known, and three of which are not. This is the wound of which Cerise's redness is only a shadow. "The Seven Treacheries guard the Neath, but there is one place more closely guarded still: a place the Masters can't touch, a place the Bazaar can't see, a place beneath St Cerise's well.