At the moment I'm practising soto Zen/zazen which I often find very hard. I love reading books by Thich Nhat Hahn and was wondering if his Zazen differs from the Japanese Soto school? If so how does his tradition do it? Also what is his tradition called?
His school is Linji Chan
-- Rinzai in Japanese, Lâm Tế in Vietnamese. It differs from Soto in some significant ways.
Well, in lineage terms, it descends from Linji, yes. But don't expect it to therefore conform to some notion of Tang or Song dynasty Linji, such as it focusing on gong'an, or the legendary "shouting and beating".
Best to say that his tradition is "The Order of Interbeing", after all, that's what he himself refers to. It is part of the whole modernist movement of Chinese / Vietnamese / etc. Buddhism that has arisen in the 20th CTY.