About Tensai

What it is

Tensai is a Japanese language dictionary and study aid for native English speakers, designed for maximum readability and efficiency to make studying less stressful and more fun.

Using Tensai you can look up the kanji, readings, and meanings for words, phrases, and individual characters in both Japanese and English, and you can do so quickly and efficiently. You can also make persistent vocabulary lists in Tensai, keeping the entries you’re interested in handy for future study and reference.

Tensai makes use of JMdict and KANJIDIC2, free dictionary files compiled and maintained by the Electronic Dictionary Research and Development Group at Monash University in Australia. Their dictionaries are free for public use and distribution as long as everyone knows who to thank for all the hard work that has been put into maintaining them.


Tensai is shareware, which means until you buy a license its features will be limited and Tensai will remind you of its unlicensed status at startup. For Tensai 0.93, unlicensed users are limited to 10 entries per vocab list. Buying a license unlocks all features in Tensai and puts you first place in line for support.

Interface Overview

Tensai's Interface


Tensai comes with two dictionaries, JMdict for Japanese to English translation of words and phrases, and kanjidic2 for individual kanji characters. The active dictionary can be changed via the toolbar popup button. In the image above, JMdict is active.

Search Types

When searching JMdict, you have 4 types of searches from which to choose: Contains, Begins with, Ends with, and Whole Words. When searching kanjidic2, the options are Textual, Stroke Count, Reading, and Meaning.


There are four ways to enter a search into Tensai:

  • By typing directly into the search field at the top right of the window.
  • By selecting a query from the search history, accessible via the magnifying glass in the search field.
  • Through the “Look Up in…” contextual menu in Tensai.
  • Through the “Look Up in Tensai” system service, available within almost any program by pressing ⇧⌘T.

Interpreting Results

Results in Tensai are formatted differently for each dictionary. They are first sorted by whether or not they exactly match the query, then by how common they are in everyday usage, and finally by their readings. Sorting in kanjidic2 is the same except results are sorted by stroke count before readings.

The below image is an example of a JMdict result. Its columns are as follows:

  1. First on the left is the frequency column, marked with a star for common or high priority entries and with a bullet for uncommon or low priority ones.

  2. The second and third columns are for compounds and readings, respectively. The first entry in the example below has multiple compounds and readings associated with it. Each compound is restricted to a particular set of readings. Occasionally a compound or reading will have extra information included in the form of an asterisk (*). Simply hover the mouse over the word or asterisk and the extra information will pop-up. Most commonly this extra info is to point out irregular or outdated use of kanji or readings.

  3. Last on the right is the meanings column. It includes the parts of speech at the top, a numbered list of definitions, and any other information the entry has to offer such as antonyms, etymologies, and fields of use. Note how two of the first entry’s meanings are limited to a particular reading.

An example of a JMdict result

The next image below is an example of a kanjidic2 result. Its columns are as follows:

  1. As with JMdict, first is the frequency column. kanjidic2 considers only the 2,500 kanji most frequently used in Japanese newspapers to be common.

  2. Second is the kanji character and its stroke count.

  3. Third is the reading column, showing the On, Kun, and Nanori readings. Kun readings sometimes contain periods — kana after such periods are the okurigana for those readings (e.g. なら.う for 習う). If a character is part of the Joyo set and has a particular grade associated with it, its grade will be displayed in this column as well. Possible grades are 1 through 6, junior high school, and jinmeiyou (kanji for use in names).

  4. Again, last on the right is the meanings column.

An example of a kanjidic2 result

Vocabulary Lists

Like playlists of songs in iTunes, Tensai offers vocab lists for organizing your entries. The vocab list drawer is opened by clicking on the leftmost toolbar button and is visible in the image below. The numbers to right of vocab list names are how many entries they contain.

  • New vocab lists can be created from the File menu, by clicking the + button at the bottom of the drawer, by choosing “New Vocab List from Selection” from the File menu, or by dragging an entry to the empty space below the list names.

  • Vocab lists can be deleted by selecting the list and clicking the - button at the bottom of the drawer or pressing the delete key. This action cannot be undone.

  • To select an entry, click anywhere in the entry not occupied by text or tab to the result view and use their arrow keys to move to the result you want to select.

  • To select multiple entries, select one entry and then ⇧-click another to add all entries between them, inclusive, to the selection. ⌘-click to toggle the selection of individual entries. ⇧↑ and ⇧↓ can also be used to grow the selection. Press escape or click in an area not occupied by any entries to clear the selection.

  • To add one or more entries to a vocab list, drag and drop an entry selection onto the desired list. To create a new list with just this selection of entries, drop onto an empty space below the existing vocab lists.

  • To remove one or more entries from a vocab list, press the delete key when entries are selected. This action cannot be undone.

An example of the vocab list drawer

Contextual Menu

Tensai’s contextual menus (brought up by right-clicking or control-clicking on selected text of an entry) will provide quick access to all of Tensai’s dictionaries. You will also be given the option to look up the selection in Spotlight, Google, the Goo online dictionary, or OS X’s built-in Dictionary application.

About Justin Anderson

I’m a recent college graduate living in New England with degrees in both Computer Science and Japanese. I enjoy eating ice cream and traveling, along with other obvious interests. I’m trying to make a living by creating Macintosh programs that I’d want to use.