A set of statements spoken at the end of a training session. not all dojos do this it often depends on the instructor or the association. Normally the after kneeling down and the mokuso (meditation) the instructor will call each statement in turn. The students then repeat it either in english or japanese,I’ve seen it done both ways.

Hitotsu! Jinkaku Kansei Ni Tsutomuru Koto!
One! To Strive For The Perfection of Character!

Hitotsu! Makoto No Michi O Mamoru Koto!
One! To Defend The Paths of Truth!

Hitotsu! Doryoku No Seishin O Yashinau Koto!
One! To Foster The Spirit of Effort!

Hitotsu! Reigi O Omonzuru Koto!
One! To Honour The Principles of Etiquette!

Hitotsu! Kekki No Yu O Imashimuru Koto!
One! To Guard Against Impetuous Courage!

It is generally believed that the principles of the Dojo Kun were passed down by Okinawan martial arts masters and the exact wording was later formalised by Gichin Funakoshi.
Seek Perfection of Character
Defend the Path of Truth
Endeavour to Excel
Display Courtesy
Refrain from Violent Behaviour

“The ultimate aim of Karate-Do lies neither in victory nor defeat, but in the perfection of the character of its participants”. (Master Funakoshi)