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What is thumb shift?

Thumb shift is a form of keyboard layout for Japanese language developed by Fujitsu for its line of Japanese word processors back in late 1970s. Although it is not recognized as an official standard it has a sizeable number of loyal followers, who obtain special keyboard or use emulation software which enables them to use thumb shift on standard keyboard. These faithful users swear that it is the ideal method to input Japanese on keyboard and I am one of those enthusiasts.

Since thumb shift was developed to rationalize Japanese input, there have been very few, if any, documents available in other languages that explain what it is like. This web page tries to fill that gap because I think the advantage of thumb shift is not limited to the Japanese language. There are so many languages in the world: it is not necessary to use keyboard primarily optimized for English for other languages.

Please take a look at an example of thumb shift keyboard.



You will notice that in place of the long space bar you see in English keyboards there are two keys that are a bit taller than other keys. There are also two smaller keys below those two keys. What are they? Before we go to the conclusion we have to look through some characteristics of the Japanese language and the difficulty that poses for processing by computers.

1. Japanese writing system

Japanese people use basically three character sets to write Japanese sentences. They are: hiragana, katakana and kanji (Chinese characters). The first two are phonetic in the sense that one character corresponds roughly one syllable. The difference between the two is its use: katakana is used for special word such as loan words from Western languages and so on and hiragana is used for other parts of the sentences. Kanji is a ideogram and it is a direct import from China.

We mix these three character sets to write Japanese characters. The use of kanji is tricky because they their use is rather arbitrary. Generally speaking, the more Chinese characters in a sentence is considered to be a symbol of writer's cleverness because mastering how to write kanji requires many years of learning. I myself do not believe in that notion. Anyway, we have to mix three character sets to write a Japanese sentence.

You can imagine the difficulty we face if we want to have Japanese sentences in prints. The print shops before electronic typesetting became common had a huge stock of typefaces. By the way, the number of characters in each set is about 80 for hiragana and katakana and very large number of kanji. Nobody knows the exact number of kanji: some dictionary lists more than 50,000 but those commonly used are some hundreds.

You can easily imagine the difficulty when we want to have Japanese sentences in print, not in handwriting. For example, we used to have Japanese typewriters (mechanical), which resemble a small print shop with a set of typefaces of several hundred characters. Typists pick up characters from the box and press the print button to type each character.

2. Writing Japanese on computers

When the word processors were invented some twenty years ago, there were several methods to input Japanese characters but gradually they all opted for the so-called kana-kanji henkan (transform) system. The basic idea is to input several hiragana (directly or through Roman alphabets --- more on that later) that correspond to a chunk of sentences and press the transform key. Since there are usually several choices, candidates for the right combination of kanji are shown and the user selects the right one. This is how the kana-kanji henkan works and it is the actual method used to input Japanese in personal computers now.

See, for example.
http://www.declan-software.com/japanese_ime/#xpuse
http://askit.uq.edu.au/itanswers/global_ime/japanese.html
http://www.threeweb.ad.jp/logos/japanese.html
The question now, is how to input hiragana from keyboard. There are basically two schools of thought: kana-nyuuryoku (kana input) and romaji-kana-nyuuryoku (Roman alphabet - kana input).

The first method is to allocate hiragana on English keyboard. Since the number of hiragana is large, it is necessary to put two hiragana on one key, using shift key. Furthermore, in most common layout (or official Japanese standard) it has become necessary to use the top row (where you have numerals and so on). If you want to input numbers, you have to change the input mode --- very inconvenient.

The second method is to use Roman characters to represent hiragana. Since most hiragana consist of a consonant and a vowel, it is necessary to type roughly twice compared to the first method. In addition to that, the layout of the usual QWERTY keyboard is not suited to Japanese input. For example, the letter 'a' is one of the most frequently used key in romaji-kana-henkan but you have to type it with the left pinkie finger, which is the least agile of all the fingers.

3. Thumb shift

Thumb shift tries to eliminate the irrationality described above. How was it made possible? The engineers at Fujitsu placed two keys (the taller ones in the picture) for the thumbs. These keys are supposed to be hit by thumb, simultaneously with the other keys. You can place three characters on one key (one without shift, one with shift on the same hand and one with shift by other hand's thumb (we call this cross shift)). In this way all the hiragana can be accommodated in the three rows, just like the English keyboard.

Simultaneously hitting the thumb and other finger sounds cumbersome but it is not at all so. Using thumb and finger simultaneously is actually the most natural behavior of human beings when grabbing something by hand. The task left is to find the most comfortable layout for Japanese input. Naturally, those characters most often used are placed in the center, typed by index and middle fingers, and on the home row. By the way, the two keys at the bottom is transform and detransform keys to change hiragana to kanji.

If you would like to see how the thumb shift works in animation please take a look at:
http://nicola.sunicom.co.jp/keyboard.htm
Flash plugin required.

4. Is thumb shift effective in other languages?

There are so many languages in the world. The IT revolution should benefit all the people in the world, regardless of the language they use. As I explained earlier, by using thumb shift, more characters can be packed in the keyboard and by selecting the most suitable layout the productivity will actually increase. This is how the IT revolution should work for the benefit of the people.

5. Some useful links

As explained above, there are only a few documents available in English regarding the thumb shift keyboard.

(1)New Vietnamese Input Method
Paper presented at the International Conference on Chinese Computing '94 in Singapore, June 1-4, 1994, by Jin Sugano of Fujitsu Limited

(2)Lolo Language Input Method
Paper presented at the Wulumuqi International CASE Symposium in Wulumuqi, October 7-9, 1992, by Tomomasa Ooka and Jin Sugano of Fujitsu Limited

Addition on Dec. 11, 2004
(3)A Better Way to Input --A case for thumb-shift keyboard--
Power Point presentation prepared by the author.


Mail to the author


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