Irish traditional music sessions are informal gatherings at which people play or sing traditional Irish music. The general session-scheme is that someone starts a tune, and those who know it, join in. Typically, the first tune is followed by another two or three tunes in a set, or medley of tunes. After a while, the set comes to an end, and after a brief interval, someone else starts another set of tunes. Sometimes there are more-or-less recognized session leaders; sometimes there are no leaders. Sessions are often held in pubs (with the hope that listeners will buy drinks for the musicians) and everyone who is able to play Irish music on an instrument is welcomed; 'grab your instrument and join along'. A pub owner might have one or two musicians paid to come regulary in order for the session to have a base. The sessions can be held in homes or at various public places in addition to pubs. The objective in a session is not to provide music for an audience of passive listeners, but in pub sessions, the punters (non-playing attendees) often come for the express purpose of listening, and the music is for the musicians themselves.
In his "Field Guide to the Irish Music Session," Barry Foy defines a session as:
"a gathering of Irish traditional musicians for the purpose of celebrating their common interest in the music by playing it together in a relaxed, informal setting, while in the process generally beefing up the mystical cultural mantra that hums along uninterruptedly beneath all manifestations of Irishness worldwide."
The sessions are a key aspect of traditional music, some say it is the main sphere in which the music is formulated and innovated. Furtherly, the sessions enable young musicians to practice in a group.
Socially, sessions (Seisiún in Gaelic) have often been compared to an evening of playing card games, where the conversation and cameraderie are an essential component. In many rural communities in Ireland, sessions are an integral part of community life.
In conclusion, sessions are an excellent way to witness the real, amorphous identity of Irish traditional tunes.