This study surveys the present situation of Optacon research in Japan and also develops further discussions on the mechanism of pattern recognition of letters by Optacon tactile reading, which has been studied so far, and various problems which need to be researched in the future. 1. As to Optacon tactile reading training program, by assembling learning steps in the order of "letters-words-phrases-sentences-passages", tactile reading ability has been effectively raised. 2. The transfer of learning effects of letter pattern components and other factors are more effective if the student first starts with learning of Katakana, then moving on to Hiragana and Kanji. 3. For Alphabets, Katakanas, Hiraganas and Kanjis of comparatively simple shape of letter, pattern discrimination of letters is possible by grasping "Critical feature: Type I". 4. However, for Kanjis of comparatively complex shape of letter, the above is insufficient, and it is necessary to reinforce the whole-part relationship of the shape of letter by introducing "analysis-compositon presentation" of the letter pattern and "Critical feature: Type II ", which can be termed as the "portrait" of the letter.5. The introduction of "Critical feature: Type II " of the letter pattern is a theory which integrates the Information theory concerning comparative matching process of the tactile input pattern of each letter with the standard pattern (prototype) of each letter fastened in one's memory, and Gestalt theory. 6. The analysis of misreading tendency of Optacon tactile reading acts "as a prominent lead in finding out mechanism of pattern recognition of letters through tactual perception. Especially misreading tendency for Kanji suggests an interesting point in that there is a common principle underlying tactual pattern recognition of the blind and visual pattern recognition of the partially sighted. 7. With due regard to the traditional Bushu classified in the Kanji dictionary (Bushu: common component of Kanji which is one of the standards in Kanji classification), it is necessary to establish new Bushu for Optacon tactile reading to make a further study of Kanji grouping for more effective pattern discrimination of letters. 8. The average number of strokes according to the Educational Kanjis introduced in each grade of elementary school increases considerably until 2nd grade, and also increases to a little extent during 3rd and 4th grade, but afterwards hardly shows any change. Therefore, there is no worry of Optacon tactile reading becoming more complex by the shape of letter becoming more complicated when the grade gets higher. 9. If an adequate guidance is provided, blind children can also comprehend the usage and the interesting points of the origin of Kanji (origin of the shape of letter) as an ideographic character (each character indicating a specific meaning). Needless to say, individual differences can be seen due to such factors as the student's age, grade, time of loss of sight, intellectual ability, abundance of tactual experience and educational environment. 10. Not only letters, numbers and symbols but illustrations, charts, and graphs can also be read by Optacon if they are not too complicated. 11. According to the usage frequency statistics of Kanji, if one masters the 996 Kanjis classified in the Educational Kanjis (Kanjis required through Grade 1 to Grade 6), one is able to read general texts consisting of Kanjis and Kanas to a considerably large extent. 12. By jointly using Optacon with not only the English typewriter and Kana typewriter, but also with "Japanese Word Processor", the usefulness of the Optacon as a reading aid for the blind is expected to increase in the future.