Left: Coimbra guitar; right: Lisbon guitar
Guitar - Cittern
The Portuguese guitar or Portuguese guitarra (Portuguese: guitarra portuguesa, pronounced [?i'ta pu?tu'?ez?]) is a plucked string instrument with twelve steel strings, strung in six courses of two strings. It is one of the few musical instruments that still uses Preston tuners. It is most notably associated with the musical genre known as Fado.
The Portuguese guitar now known has undergone considerable technical modification in the last century (dimensions, mechanical tuning system, etc.) although it has kept the same number of courses, the string tuning and the finger technique characteristic of this type of instrument.
It is a descendant of the Medieval citole, based on evidence of its use in Portugal since the thirteenth century (then known as 'cítole' in Portuguese) amongst troubadour and minstrel circles and in the Renaissance period, although initially it was restricted to noblemen in court circles. Later it became popular and references have been found to citterns being played in the theater, in taverns and barbershops in the seventeenth and eighteenth century in particular.
In 1582, Friar Phillipe de Caverell visited Lisbon and described its customs; he mentions the Portuguese people's love for the cittern and other musical instruments. In 1649 was published the catalogue of the Royal Music Library of King John IV of Portugal containing the best known books of cittern music from foreign composers of the sixteenth and seventeenth centuries, in which the complexity and technical difficulty of the pieces allow us to believe that there had been highly skilled players in Portugal.
The angel playing the cittern (c.1680), a sculpture of large dimensions in the Alcobaça Monastery, depicts in detail the direct ancestor of the Portuguese guitar. In the first half of the eighteenth century, Ribeiro Sanches (1699-1783) had cittern lessons in the town of Guarda, Portugal, as he mentions in a letter from St. Petersburg in 1735.
In the same period there are other evidence to the use of the cittern alluding to a repertoire of sonatas, minuets, etc. shared with other instruments such as the harpsichord or the guitar. Later in the century (c. 1750), the so-called "English" guitar made its appearance in Portugal. It was a type of cittern locally modified by German, English, Scottish and Dutch makers and enthusiastically greeted by the new mercantile bourgeoisie of the city of Porto who used it in the domestic context of Hausmusik practice. This consisted of the "languid Modinhas", the "lingering Minuets" and the "risqué Lunduns", as they were then called. The use of this type of guitar never became widespread. It disappeared in the second half of the nineteenth century when the popular version of the cittern came into fashion again by its association with the Lisbon song (fado) accompaniment.
The last detailed reference to the cítara appeared in 1858 in J.F. Fètis' book The Music Made Easy. The Portuguese translation includes a glossary describing the various characteristics (tunings, social status, repertoire, etc.) of both cittern and "English" guitar of the time.
The Portuguese guitar is used for solo music as well as accompaniment and its wide repertoire is often presented in concert halls and in the context of classical and world music festivals all around the world.
Two distinct Portuguese guitar models are built: the Lisboa model and the Coimbra model.
The differences between the two models are the scale length (445 mm of free string length in Lisboa guitars and 470 mm in Coimbra guitars), body measurements, and other finer construction details. Overall, the Coimbra model is of simpler construction than the Lisboa model. Visually and most distinctively, the Lisboa model can easily be differentiated from the Coimbra model by its larger soundboard and the scroll ornament that usually adorns the tuning machine, in place of Coimbra's teardrop-shaped motif. Lisboa guitars usually employ a narrower neck profile as well. Both models have a very distinct timbre, the Lisboa model having a more bright and resonant sound, and the choice between the both of them falls upon each player's preferences.
As early as 1905 luthiers were building larger Portuguese guitars (called guitarrão, the plural being guitarrões), seemingly in very small numbers and with limited success. Recently, the famed luthier Gilberto Grácio has built a guitarrão, which he named a guitolão instead; this instrument which allows for a wider timbric range, on the low and the high end, than a regular Portuguese guitar. 
The technique employed to play the Portuguese guitar is what is historically called dedilho. This technique comprises playing solely with the thumb and the index fingers and it was inspired by the technique used to play "viola da Terra da Terceira". On the Portuguese guitar the strings are picked with the corner of the fingernails, avoiding contact of the flesh with the strings. The unused fingers of the picking hand rest below the strings, on the soundboard. Most players use various materials in place of natural fingernails; these fingerpicks were traditionally made of tortoiseshell, but today are usually nylon or plastic.
Armandinho, born in 1891, became one of the most influential guitar players in Lisbon, leaving a vast repertoire of variations and fados behind. Following in his footsteps came other guitarists, such as Jaime Santos, Raul Nery, José Nunes and Fontes Rocha. Artur Paredes, born in 1899, was an equally important player in the city of Coimbra. Much of today's Coimbra guitar features can be traced back to his contact with local luthiers. His son Carlos Paredes was a virtuoso and attained great popularity, becoming the most internationally known Portuguese guitar player. His compositions on the Portuguese guitar go beyond the traditional use of the instrument in fado musicianship giving him (and the instrument) a status above folk or regional music. This solistic tradition has been followed till today by several outstanding musicians such as Pedro Caldeira Cabral, Antonio Chainho, Ricardo Rocha, Paulo Soares and several other virtuouso guitarists of the younger generation.
The Portuguese guitar played a small role in Celtic and western folk music following the folk revival. In the 1970s, Andy Irvine of the band Planxty played a modified Portuguese guitar. British luthier Stefan Sobell based his early 1970s creation of the modern cittern on a Portuguese guitar he'd bought at a used shop in Leeds some years previously.
There are many Portuguese guitar makers still building guitars, according to traditional craftsmanship. Many families have passed on their knowledge for generations. Amongst the most notable guitarreiros, or guitar makers, are the Grácio family, Álvaro Ferreira, the Tavares family (now living in Toronto Canada), the Cardoso family, António Guerra, Domingos Machado and Domingos Cerqueira. The Grácio family and Álvaro Ferreira's instruments are usually considered as the pinnacle in terms of quality, although these instruments are very hard to find and can be quite expensive.
The tuning chiefly employed on the Portuguese guitar was historically called afinação do fado or afinação do fado corrido. It was probably developed in the early 19th century, as it was already largely adopted by Lisbon's fadistas by the mid-century. With the diminishing use of the natural tuning (see below) by players, this tuning came to simply be called either afinação de Lisboa, when tuned high, in D, or afinação de Coimbra, when tuned low, in C; this stems from the fact that while most Lisbon fado players tuned their guitars in D, in Coimbra the students came to tune theirs in C as standard practice, mainly through the influence of Artur Paredes. It is important to note, however, that regardless of the difference in pitch between the two variations of the tuning, in practice, the latter still makes use of the former's aural conventions, as such a C is called D, a D is called E, etc., by the players (essentially making a Coimbra-tuned Portuguese guitar a transposing instrument similar to a B-flat trumpet in that a given note is referred to by the note name a whole step higher than the note name that concert-pitch conventions would use).
The natural tuning, inherited from the English guitar of the 18th century, was also very frequently employed up to the first half of the 20th century, being preferred to the former by some late-19th-century players; it was frequently tuned in E instead of C, as this simplified the change between the fado tuning for players who used both. Some variations of this tuning were also adopted, such as the afinação natural com 4ª, also known as afinação da Mouraria, or the afinação de João de Deus, also known as afinação natural menor. The natural tuning and its variations have been for the most part, out of practice for several decades.