Ideally the diagonal lines would all be parallel - note mine aren't! The bindu of the candra-bindu gives the smallest unit - the nib width. In western calligraphy the nib width is critical to understanding the design of a script. Here though we do find half-widths partly because the pen is always (supposed to be) at 45°.
Horizontally the body of the syllable is about 3 nibs wide - with some extension beyond in the outer details (the tail of the ha for instance). Vertically the main part of the ha is 4 nibs. The candra-bindu is about 2.5; while the ū is about 2. In an ideal world the ratios height to width of the ha, and the height of the candra-bindu to the height of the ha would approach the golden ratio ~ 1.618.
Without being perfect this figure points to where perfection lays. And there is a deep truth here that Buddhism taps into. There is a Mahāyāna sūtra which describes the whole world as a scroll, and all the dharmas, all the mental phenomena, as letters on that scroll. However the sūtra says that each letter contains the whole of the Buddhadharma. In other words each and every experience we have is pointing towards the same truth - that experience itself is insubstantial and unsatisfactory.
By a deep analysis of the flaws of my calligraphy I come to see where I might improve. I gain a deeper understanding of the way this script works, and with it a deeper understanding of my own experience of the world. Gradually I improve. I began, as all beginners do, copying the work of masters - my master was not present to correct me, but I could see his calligraphy, and I was able to correct myself. This is a slow way to make progress I may say. It is much better to have a teacher - but I am somewhat stubborn and Siddhaṃ calligraphy teachers are hard to come by. Even so after some years I have come to my own understanding of the form. I would not say that I have mastered the art, but I know good from bad calligraphy these days, and I am usually honest with myself about my own efforts. One needs to be critical without being harsh, which is a fine line sometimes.
Calligraphy is a fascinating art because each time one writes something, even after years of practice, there are variations. Training oneself to notice these variations is important. It is all part of Buddhist practice. We have to see clearly what has been done, comparing it with the intention, with the template one is trying to copy - whether it is the syllable executed by a master, or the internal model that develops with time - to see how we have deviated from our aim. We may even come to understand why we deviate.
Achieving perfection is definitely the goal, but in the meantime we focus on the striving for it - on the technique. Along the way one sometimes reaches a milestone in understanding and practice. It's good, in my opinion, to celebrate these milestones. I often post something on my blog or on Flickr that seems especially good. Then in a few months or years one can look back and see the imperfections and wonder at one's own superficiality and naivety! LOL! I look at the calligraphy on my own website and think that most of it is poor, some of it very poor. It was the best I could do at the time, but now I know I can do better.
When doing calligraphy it is good to be aware of your body, your breathing. Your whole body contributes to the process - not just the hand. One must have a firm base for instance. The hand and arm are connected to the trunk by many muscles and sinews. In order to have a free hand, one must have free shoulders, for instance. And of course in order for the body to be relaxed and free, the mind must be relaxed and free. The lack of calm and freedom is the main source of imperfection in calligraphy. This is perhaps why some of the greatest calligraphers of Japan -- Kūkai, Hakuin, Ryōkan -- have also been masters of meditation.
A single syllable can be a challenging practice. We tend to do the syllable again and again. Mantras of several syllables give a different challenge - each syllable in a mantra like oṃ maṇipadme hūṃ has it's own form and harmony. The intense focus of the bīja must broaden out to encompass the multiplicity of forms. A long mantra, like the 100 syllable Vajrasattva Mantra or some of the long dhāraṇīs are another challenge. When working with ink on paper, the slightest lapse in concentration results in an error. The paper is then ruined and one must start again. I once did calligraphy of the Heart Sutra which is almost 500 syllables. The effort was a great strain and I don't know if I could manage it again! 500 syllables without a significant error in writing. This took careful planning and study of the Sanskrit, and was certainly not achieved on the first attempt. It is the sort of thing best attempted whilst on a solitary retreat I think.
Clearly calligraphy is a good śamatha practice, but it has the potential to be a vipaśyanā practice as well. The close examination of the tiny differences, and the attention to what happens when we set off to write something, can allow us to see just how our mind works to create experience. The interconnectedness of mind and body, and the interplay of the two in calligraphy show us something about the interconnectedness of the phenomenal world.
Those who merely cut and paste, or who use fonts instead of spending years learning the script and putting in the 100s and the 1000s of hours required to become proficient, are really missing the point. Some people seem to think that calligraphy is just images to be consumed, owned or tattooed. But that is only the most superficial and naive response to the art. Perfection is something that we each, individually strive for. Without the striving there is no perfection. Simply copying the master is not enough, even if one does it by hand. Owning an image is truly worthless. On his funny, if coarse, blog "Shit my Dad says" Justin Halpern recalls showing off his newly acquired cellphone to his now infamously cantankerous father. Dad replies:
"Son, no one gives a shit about all the things your cell phone does. You didn't invent it, you just bought it. Anybody can do that."
My own favourite calligrapher (there aren't that many of us) is Tashi Mannox (website and blog). Tashi first trained as an artist, and then spent 17 years an a monastic scribe. It shows both in his art, and in his manner (I would say from our correspondence and one meeting ). Tashi makes amazing and inspiring works of calligraphic art, I would say he's a master calligrapher. But in some ways I prefer my own calligraphy, because it is the result of my own striving. I draw inspiration from Tashi's work, but I would never be content merely to own something he did (though I do have a few samples he kindly gave me when I visited him in London a couple of years ago). I learn so much more from keeping up my own practice. I hope that others are inspired to take up the art of calligraphy - it has been a very rewarding practice for me.