In the Middle East, but especially Islam, the concealment of belief, as a method of self-protection. Taqiyya is allowed, and performed, when necessary to avoid death or injury to oneself or other Muslims. Taqiyya is mainly considered as a part of Shi'i theology or modern-day Islamism.
Taqiyya may be translated with 'fear' and 'caution'. It is closely related to the term katm or kitman, 'concealment'. Taqiyya is in many cases linked with regulations of how Muslims should act with non-Muslims.
The rules concerning the true intention of taqiyya are strict, and abusers of taqiyya will be punished by God.
The permission to conceal the faith is believed to be admitted by the Koran:
Koran sura 16: The Bee
108 ... unless it be one who is forced and whose heart is quiet in the faith...
Koran sura 3: Imran's house
27 ... If you hide that which is in your breasts, or if you show it, God knows it...
Some interpret Muhammad to have performed taqiyya, too, when migrating to Yathrib (later Madina) instead of risking his life staying in Mecca. This interpretation may seem doubtful, but has importance with Muslims in order to legitimize taqiyya. It must be stressed that the two Koran verses above seem to allow acts of taqiyya; they even seem to allow it indiscriminately, meaning that it is up to the individual to decide when it is fit to conceal all or parts of his/her faith.
Traditionally, a majority of Sunnis will not accept taqiyya, arguing that it is an expression of lack of faith in God. Yet, there are Sunni theologians who defend the use of taqiyya, stating that the faith in the heart is what counts, not outward expressions, like with the historian and theologian at-Tabari (dead 923).
With several Shi'i groups, like the Twelvers and the Zaydis, taqiyya has been defined as a fundamental tenet of faith. In some cases, taqiyya has been held as a distinguishing factor between them and the Sunni majority. There are many stories of Shi'i heroes breaking the regulations of his religion to achieve his goals. Unnecessary martyrdom is something that a Shi'i should avoid. With the Assassins, a Shi'i orientation, taqiyya has been an important technique. Entering taqiyya should be done with a niya, the intention, in order to clarify the true intention to conceal one's ideas.
Also, the Ibadis allow the use of taqiyya. Among the Ibadis it is said that "the taqiyya is a cloak for the believer: he who has no religion has no taqiyya."
All this may be seen in terms of who have been dominating the Muslim world over the centuries and not. For Shi'is taqiyya has been seen as vital for the survival of individuals and sects, while Sunnis most of the time have not had to take such considerations.
With modern day's immigration to Western societies, it appears that even Sunnis have applied a Shi'i-like use of taqiyya to avoid different problems with their new societies.
Rules as to when taqiyya is permitted and not, has been set down. A Muslim facing corporal punishment or imprisonment may not perform taqiyya to avoid this. A male with family responsibilities may perform taqiyya if his wife(s) and children are in danger.
In recent years, taqiyya has often been used by militant Islamists, who usually are Sunnis. In preparation for terrorist attacks, using taqiyya has been part of covering their tracks. The world saw a very illustrative example of taqiyya with the 911 (September 11, 2005) attack on USA, when the local al-Qaida leaders went to bars and drank alcohol shortly before initiating their suicide attacks.
Facing persecution from Muslims, some religions of the Middle East have accepted to be labelled as belonging to Islam. For more, see Taqiyya religions, which involves about 22 million people.