The Ronin tells the story of a masterless samurai who lives a violent, debauched life until one day he is made aware of the enormity of his crimes. As a sort of penance, he decides to dig a tunnel through a mountain which can only be crossed by a high and dangerous pass.
The book is based on a Zen koan (a problem which cannot be solved by logic, on which practitioners of Zen meditate in order to find enlightenment).
The Ronin is a fascinating book and many years later, I am still troubled by the tough questions that it posed, such as: are we only good because we have to be; is there justice in revenge; and can human beings ever really make up for the terrible things that they do?
This was my favourite book when I was in high school and although now that I am older and can see that there are a lot of weaknesses in the book, I still say that it has the best ending of any book I have ever read and highly recommend it.