5. Take the tune in the left hand and use the thirds and the sixths in the right hand and repeat the steps 1 through 4. By now probably you are starting to realize that we are developing your left hand technique while the right hand plays the hymn tune only. This step will teach you how to play faster notes in the right hand as well. Now play the hymn tune in the left hand as written but add an extra voice in the right hand, first note against note as in step 1. You may sometimes use the notes from the bass line in your right hand, but it will not always sound nice.
By the way, the technique when you invert the voices and play the top voice in the bass and vice versa is called invertible counterpoint. Invertible counterpoint is indispensable polyphonic trick to use if you want to create any imitative polyphonic piece, as invention, fughette, or a fugue. As I mentioned before, this technique will not always work with your hymns, because there will be instances when you will find the interval of the fifth between the original bass and the soprano voice which in inversion will become a forbidden fourth (it is not actually forbidden, but its use is greatly limited and specialized).
At any rate, the best way to construct your new soprano line in this step is to use the thirds and the sixths against the bass which always sound nice and sweet. After note against note exercise becomes easy, play two against one, three against one, and finally, four against one as you did in the steps 2 through 4.
6. Alternate motion between the hands. Steps 1 through 5 will develop your hand independence and teach you about a special kind of polyphony – contrasting polyphony - where voices are independent but very different both melodically and rhythmically. However, if you want to move your hand independence and polyphony to the next level, step 6 will do exactly that. It is called imitative polyphony when voices are independent but at the same time they have much in common – they imitate each other either melodically or rhythmically or both.
In order to achieve that, try to alternate movements between the hands. For example, in measure 1 let the soprano move in faster notes, in measure 2, this will be done by the bass part etc. You see, one voice is stationary while the other moves; then they switch roles. After practicing this way for a while, you can alternate the motion every 2 beats and later even every beat. By the way, one hand can play step 2 and the other step 4 as well!
By practicing this way you can create nice choral partitas or variations which will also enhance your service playing. You can use these variations for hymn introductions or preludes. As promised, these steps will help you to develop your hand independence using two voice texture or bicinium, of course, but without knowing, actually, you will be improvising as well. In order to achieve the greatest results, I recommend you choose at least 10 different hymns and work your way through each of the above steps at a slow tempo. Do not proceed to the next step unless you can play slowly (but fluently) the previous step at least three times in a row correctly.
By the way, would you like to know more about any aspect of hymn playing on the organ? Please share them in your comments below and I will do my best to answer your questions.
By the way, do you want to learn to play the King of Instruments - the pipe organ? If so, download my FREE video guide: "How to Master Any Organ Composition" in which I will show you my EXACT steps, techniques, and methods that I use to practice, learn and master any piece of organ music.