Handbook of Liturgical Practice of the Russian Church Abroad
There are two basic ‘styles’ of ryassa within the Orthodox world: the so-called ‘Russian Style’ and the ‘Greek Style’ (with various lesser modifications of each of these also existing). Within the Diocese of Great Britain and Western Europe, it is the Russian-style ryassa that is to be worn by all clergy (but see exceptions, below).
An example of a Greek-style ryassa, characterised by its overall rectangular shape, fastened only at the neck and which therefore remains open along a long, straight seam at the front.
An example of a Russian-style ryassa, as is blessed to be worn by all clergy of our Diocese. It is characterised by its differently-shaped cut, sleeves that are broad at the wrists but taper towards the torso, and a front that is fastened both at the neck and at the waist.
Explanation and exceptions: It is important to our Ruling Bishop that the unique traditions and characteristics of our specifically Russian Orthodox liturgical heritage be preserved and maintained. For this reason, His Grace blesses that all clergy wear the Russian-style ryassa, and not the Greek-style ryassa. However, an exception is made in the following circumstance: if a clergyman does not own a Russian-style ryassa but only one of the Greek style, he may continue to wear this until such time as he can replace it with a Russian-style version — which should be done as soon as possible. If financial concerns or other issues pose a challenge to replacing a Greek-style ryassa with one in the Russian-style, the clergyman should contact the Diocesan Chancellery, who will strive to provide assistance in making this possible.
Newly-ordained clergymen are to secure a Russian-style ryassa from the outset.