Though promoted as types of meditative techniques, in fact all of these are intended to as ways of being in the world; and as a result of being in the world in a certain way.
1. Shikantaza = Just Precisely Sitting. Promoted by Dozen Zenji as the proper way to do zazen.
2. Zazen = Sitting Absorbed. Comes from Zenna (Absorption Meditation); which is said to be the meditation Shakyamuni Butsu found himself, both naturally as a child watching his father work, and when sitting under the 'Bodhi' tree to awaken. Absorption Meditation means to be absorbed into reality as it is, as Reality itself absorbs us... so there is no separation between us. We are living in Reality, and Reality lives in us. This is said to be our natural human state, which results in natural humane behavior. In Zen all other meditations are thought to be the result of living in Zenna. Though they can be used as meditations in and of themselves, they should eventually lead one to be in Zenna, so that they should be, not just a meditative technique, but will be naturally a part of our lives.
3. Meiso- Japanese Meditation. As most cultures, the Japanese too, always had their own meditations as well; these are usually put under the category of meiso. Since it's used for many meditation, the meaning of each character takes no various connotations according to it's use. But generally relates to the natural sitting of the mind. Me relates to the eyes, and often is said to be eyes closed, or eyes resting (often interpreted as 1/2 closed in a natural resting position). 'i' is harder but deals with nature and natural. So is the mind or thoughts, which should rest naturally like the eyes. In this way there is no separation between Nature, our body (eyes), and our mind. Meiso can be used with all of the Zen Meditations as they descended to it through it's Buddhist heritage.
4. Nen-Meiso = Nen is Mindfulness. Mindfulness Meditation means to be aware of all time/space... Of our place in relation to all time/space. It has the meaning of both being right here / right now and also remembering all here's and all now's... thus connection past-present-future as one here now. This is often used as a Meditation in Daily Life during all of our daily activities. Nen-Meiso is the natural result of living in Zenna.
5. Kan-Meiso = Kan is Insight; or to see clearly into reality... Looking deeply into Reality.
6. Kida-Meiso = aka Sanmai; This is to be established; focused; concentrated; determined.
7. Jaku-Meiso = Tranquility.
8. Kakusoku = Immediately Awake. This is an interesting type of awareness, where it settles no where, with no distinction. Naturally, immediately we are awake. This is often thought to be the true teaching of Soto-shu Zen.