Wikipedia: Nihilist cipher

In the history of cryptography, the Nihilist cipher is a manually operated symmetric encryption cipher originally used by Russian Nihilists in the 1880s to organize terrorism against the tsarist regime.

First the encipherer constructs a Polybius square using a mixed alphabet. This is used to convert both the plaintext and a keyword to a series of two digit numbers. These numbers are then added together in the normal way to get the ciphertext, with the key numbers repeated as required.

During World War II, several Soviet spy rings communicated to Moscow Centre using two ciphers which are essentially evolutionary improvements on the basic Nihilist cipher. A very strong version was used by Max Clausen in Richard Sorge’s network in Japan, and by Alexander Foote in the Lucy spy ring in Switzerland. A slightly weaker version was used by the Rote Kapelle network.

Wikipedia: Depressive realism

Depressive realism is the hypothesis that depressed individuals make more realistic inferences than non-depressed individuals.

Although depressed individuals are thought to have a negative cognitive bias that results in recurrent, negative automatic thoughts, maladaptive behaviors, and dysfunctional world beliefs, depressive realism argues not only that this negativity may reflect a more accurate appraisal of the world but also that non-depressed individuals’ appraisals are positively biased.

This theory remains very controversial as it brings into question the mechanism of change that cognitive behavioral therapy for depression purports to target.

Wikipedia: Three Hundred and Thirty Five Years’ War

The Three Hundred and Thirty Five Years' War was a theoretical state of war between the Netherlands and the Isles of Scilly (located off the southwest coast of Great Britain).

It is said to have been extended by the lack of a peace treaty for 335 years without a single shot being fired, which would make it one of the world’s longest wars and a bloodless war. Despite the uncertain validity of the declaration of war, and thus uncertainty about whether or not a state of war ever actually existed in the first place, peace was finally declared in 1986.

In 1985, Roy Duncan, historian and Chairman of the Isles of Scilly Council, wrote to the Dutch Embassy in London to dispose of the myth that the islands were still at war. Embassy staff found the myth to be accurate and Duncan invited the Dutch ambassador Jonkheer Rein Huydecoper to visit the islands and sign a peace treaty.