Thumb-shift keyboard
A Japanese keyboard design using thumb keys for faster input.
The thumb-shift keyboard (親指シフト, oyayubi shifuto) is a layout designed for typing Japanese on word processors and computers. Fujitsu developed it in the late 1970s, and it debuted in 1980 as part of their OASYS line of Japanese word processors, aiming to make input easier, faster, and more natural. It remains favored by those who type large volumes of Japanese text—such as writers, playwrights, and lawyers—due to its ease of use and speed. In 1989, the rights to this design were transferred to the Nihongo Nyuuryoku Consortium (Japanese Input Consortium), a technology-sharing cooperative of interested companies. The layout is also cited as an example in Japanese Industrial Standards.
When Japanese word processors emerged in the late 1970s, a major challenge was how to input Japanese sentences. The writing system uses three scripts—hiragana, katakana, and kanji—with roughly 80 characters for the kana and thousands for kanji, far too many for a standard keyboard. Kanji proved especially difficult. Developers tried various approaches, such as handwriting recognition, large tablet-style input devices, and assigning multiple key-codes per character, but the method that became standard was kana-kanji transformation. This works by typing a transliteration (in kana or Latin letters, known as rōmaji), and the computer’s dictionary converts the input into kanji. The software handling this is called an input method editor.
Earlier, two main input methods existed: using the Roman alphabet or using hiragana directly. The romaji-kana system typically relies on a QWERTY keyboard. The JIS kana system places hiragana on the keys, but because there are so many, it uses not only the letter keys but also the top number row. Additionally, some characters require the shift key, similar to typing uppercase letters in English.
Both methods have drawbacks, despite working with widely available keyboards. In the JIS kana layout, some characters sit on the number row, far from the home row, increasing the chance of typing errors. Numbers also pose a problem, as they share key positions with certain characters. With romaji input, keystrokes increase: most kana need at least two keystrokes, compared to one for direct kana input. On average, typing Japanese sentences in romaji requires about 1.7 times more keystrokes than using kana.
- Inventor
- Fujitsu
- Year invented
- late 1970s
- Year released
- 1980
- Rights transferred to
- Nihongo Nyuuryoku Consortium (Japanese Input Consortium)
- Year rights transferred
- 1989
- Peak market share
- 20 percent (of Japanese word processor market, not all OASYS models equipped with thumb-shift)
- Top speed
- exceeds 250 characters per minute
Lore & Background
The engineers at Fujitsu, led by Yasunori Kanda, who were developing Japanese word processors, first tried to use simultaneous pressing of multiple character keys to differentiate hiragana characters but found it difficult to use. They then came up with an idea of using the thumb in conjunction with other fingers. Unlike the shift action with the little finger on an English keyboard, this method uses simultaneous pressing by the thumb and another finger. This enables each key to be conjugated in three ways: without thumb action, with the same-hand thumb, and with the thumb of the opposite hand, allowing the keyboard to accommodate half as much more characters than usual. Simultaneous pressing with the thumb is considered more natural than the shift action with the little finger because thumbs are much stronger than little fingers. Since this was a new concept, it was possible to choose a better layout of characters, taking into account such parameters as frequency of occurrence, sequencing of characters and phonological structure of the Japanese language.
Fujitsu's first Japanese word processor, named OASYS, with thumb-shift keyboard was launched in 1979 and became a big hit. The share of OASYS in the Japanese word processor market reached 20 percent at one time, though not all OASYS were equipped with thumb-shift keyboard. Adoption was slow to spread to other manufacturers' product lines. Although Fujitsu was open to adoption by other manufacturers, there was little incentive for them to adopt their rival's system in the fiercely competitive environment of the word processor market. It was only in 1989 when Nihongo Nyuuryoku Consortium was established with a participation of several companies, including Fujitsu, Sony, Apple Computer, Japan IBM and Panasonic, as the promotion body of thumb-shift. The rights regarding the use of thumb-shift were officially transferred from Fujitsu to the Consortium. As of October 2011, three models of thumb-shift keyboard for PC, as well as two portable PCs are on sale. NICOLA is a variation of thumb-shift keyboard where Henkan is merged with right thumb-shift and Muhenkan merged with left one because USB HID does not allow additional key left thumb-shift and right thumb-shift.
Reader's Guide
The thumb-shift keyboard is notable for addressing the challenges of inputting Japanese sentences, which use three character-sets (hiragana, katakana, and kanji) with a large number of individual characters. Conventional methods, such as the JIS kana system and romaji input, had drawbacks: JIS kana placed some characters far up in the numbers row, increasing typing error risk, and numbers shared key positions with characters; romaji input required roughly 1.7 times the keystrokes of kana input. The thumb-shift design solved these by placing all hiragana in the 30 most used keys, using rational character allocation, and employing simultaneous thumb hits. Its advantages include ease of use, faster learning, and faster writing speed. An experiment with beginning typists showed thumb-shift users consistently outpaced those of JIS kana and romaji-kana. Many top typists in word processor speed contests use this system, with top speeds exceeding 250 characters per minute. However, the major drawback is that it requires special hardware with two thumb-shift keys at the center bottom, which is most serious in portable computers with fixed keyboards. Although some try to emulate thumb-shift using conventional keyboards, results are mixed. The user base remains small.
Did You Know?
- The thumb-shift keyboard was invented by Fujitsu in the late 1970s and released in 1980 as a feature of the OASYS line of Japanese word processors.
- The rights to the thumb-shift design were transferred to the Nihongo Nyuuryoku Consortium in 1989.
- The top typing speed on a thumb-shift keyboard exceeds 250 characters per minute in completed sentences after kana-kanji transformation.
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