takahi_i from ATL here.

RedPen v1.4 has been released. RedPen v1.4 can be downloaded from the URL below. Also, if you are using MacOS, you can install RedPen v1.4 using Homebrew.


The jewel in the crown of release v1.4 is LaTeX compatibility and function reinforcement. Each of these topics is explained below.

LaTeX Compatibility

This release starts compatibility with the LaTeX format. LaTeX support has come about due to many requests since the early days of RedPen development. This build is finally compatible more than a year since the release of v0.6.

Unfortunately, the current LaTeX support has the following limitations.

  1. RedPen’s LaTeX parser does not operate correctly when you add your own tags using a macro
  2. Not compatible with searches for sentences in lists

Despite these major limitations, beginners can probably use it to search essays and documents.

Functions Reinforcement

v1.4 has intensive function (Validator) reinforcement. There are types with added functions: one with both Japanese and English compatibility, one with Japanese compatibility only, and one with English compatibility only.

Functions with both Japanese and English Compatibility

  • DoubleNegative: Double-negative sentences are difficult to understand in both English and Japanese. DoubleNegative outputs an error if a double negative is found in a sentence.

Functions with Japanese Compatibility Only

  • Okurigana: Outputs an error if the Japanese okurigana differs from regular use. For example, the following sentence uses incorrect okurigana.

費して” is incorrect; it should be “費やして“. Okurigana outputs an error if the above sentence is found in the input document.

  • DoubledJoshi: Using the same particle twice in one sentence makes the sentence difficult to read. The possessive “の” is particularly overused. See the following sentence, for example.

“の” is used twice in the sentence, and the “の” particles increase the ambiguity. Replacing the “の” as shown below emphasizes the point that this a document input and makes the sentence easier to read.

Functions with English Compatibility Only

  • FrequentSentenceStart: When writing a document in English, adjacent sentences often start with the same expression. Starting sentences with the same expression is bad style, so we want to replace it promptly. See the following example.

In the above example, two adjacent sentences both start with “we“. Replacing the subject of the second sentence prevents continuous use of the same initial expression without changing the meaning.

  • UnexpandedAcronym: Searches for source word strings (unabbreviated) for words that have been abbreviated. For example, if the abbreviation SVM is found in a sentence, an error is output unless the source term Support Vector Machine is also found in the document.
  • WordFrequency: Outputs an error if the frequency of a word in the document is different from general cases.
  • Hyphenation: Outputs an error if hyphen usage is not general.
  • NumberFormat: Outputs an error if the numerical expression is different from general English usage.
  • ParenthesizedSentence: ParenthesizedSentence: Searches for the use of parentheses. Outputs an error if nested parentheses or parentheses greater than specified are found in the sentence.
  • WeakExpression: Outputs an error if an ambiguous English expression is found in the sentence. For example, words such as completely and huge should be replaced with more accurate expressions.

Development of Version 1.5

Ongoing development of RedPen version 1.5 is scheduled. In truth, it is not yet a priority, but it has been decided that v1.5 will include mechanisms for written using JavaScript. Build expansion to enable English functions to work in Japanese is also scheduled.

Further, the release of v1.4.1 with several bugs that have currently been reported having been corrected is scheduled before the release of v1.5. I ask you all for your future support.