The speech on the comparison between the two Mahaya branches i.e. Pure Land and Zen Buddhism was in 1998 at Kagyu E-Vam Buddhist Institute. Both Zen and Pure Land Buddhism are common in the Vietnamese community and are practiced in the same society. The difference between the two traditions is how they end suffering. The two traditions aim at attaining full enlightenment.
There is a lot of stories about waves and water in Zen. The wave depends on water and weather conditions. Self attachment is the cause of suffering in life. Zen urges us to detach ourselves from self. Buddhists should mirror their mental actions and squash them off so as to have a peaceful mind. Zen aims at attaining a tranquil mind which is not attached to any mind, and it is the unique Buddha mind. Zen requires us to live a selfless life, not attached to anything. This prevents destruction and disappearance.
As the name depicts, Pure Land means a land which is perfect. It is about being pure of greed, ignorance, hatred and defilement. There are four pure lands for Dharmakaya Buddha body, treasure body, arhats and pure land of Amitabha Buddha. People can get a new rebirth from the pure land and attain full wisdom the way Zen proposes. The Zen is the process of attaining that level of selfless while the Pure Land Buddhism is not as tiresome as Zen. In Zen, a person may die leaving behind some karma which will demand to take another reincarnation for purification. Pure Land Buddhists get worried about reincarnation. One of the pure lands made a commitment to create a pure land where people can be reborn.
The Zen practice is concern with self discipline, and a reflection of the mind is particularly emphasized. Zen uses the concept of awareness. Awareness creates an insight on difficult situations, which is a supporting tool, for the Zen tradition. Pure Land, on the other hand, is practiced. One must have faith in Amitabha Buddha that he has compassion, and pure land is created by him. In Pure Land, people remember Buddha by visualizing, reciting and understanding Buddha's scriptures. Pure Land is all about trusting Amitabha Buddha. Zen insists that pure land lies in the mind. Pure Land seems effortless as opposed to Zen.
Zen tradition is perfect if a person understands the Buddha-mind. One will always remain without any sin which is the ultimate goal of Buddhism. The mind may be too stern to get what is right. Pure Land should be practiced if we can not get Buddha mind. Amitabha Buddha helps people achieve Pure Land, so they can attain Buddha-mind.