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What are categories?

When you work with a collection which includes material belonging to different subjects, you will want to keep different subjects in different sections of the knowledge tree (in the contents window). You will also want to design a different look for items related to literature, and a different look for questions related to mathematics. For example, you will use pictures to illustrate your anatomy branch, sounds to illustrate your foreign language section, spell-pads to make your spelling section work best, etc.

To help you keep different subjects in one collection, SuperMemo introduces the concept of a category. A category is a section of the knowledge tree. It is used for keeping material related to a single subject. Elements added to a given category may use their own template that determines their look (e.g. images, sounds, colors, fonts, sizes of text fields, number of shape components, etc.). It is highly recommended that you learn about templates before using categories. See: Using templates

Once you understand the concept of the category, it will become very easy to manage a large number of items belonging to entirely different areas of knowledge.

Creating a category

You can easily create a new category using the following steps:

  1. choose Edit : Create category
  2. choose a branch in the knowledge tree where a category should be inserted and click Next
  3. type in Category name (e.g. geography, biology, etc.) and click Next
  4. if you want your category to use a template created earlier use Change buttons to select a new template. If you are not sure about templates, click Finish and SuperMemo will use default templates for your category. You can change templates later by means of View : Categories. Template for items will determine the look of your question-answer items in the category. You can also choose other template formats for items (e.g. occlusion test, multiple choice test, etc.). Template for topics will determine how your category articles will look like (e.g. when you import them with Ctrl+Alt+N in incremental reading)


Category properties

If you would like to change category properties, choose Search : Categories on the main menu. You will see the category registry with all categories that you have defined until now:

Each category in the registry is characterized by the following properties (compare with the picture above):

Using category registry

The category registry can be opened with Search : Categories on the main menu. Category registry is useful in the following circumstances:

  1. If you want to change the name of a category, use Rename in the category registry
  2. If you want to change the template used for items in the category, click the Template button in the category registry, select a new template from the template registry and choose Accept
  3. To delete a category, choose Delete in the category registry
  4. To decide if template should be applied automatically when moving items into the category , use auto-apply button

It is not recommended to change Root or Hook manually (unless you fully understand the way SuperMemo builds category folders under the category root)


Here is the typical way of working with categories:

  1. Use Edit : Create category to create a category
  2. Use Ctrl+Alt+M to save the default item template (or use Search : Categories to change category templates)
  3. To start adding items to another category (e.g. to start working with Chemistry after finishing your work with Geography), choose the new category in the category combo-box on the Tools toolbar
  4. To move items from To Do category to a target category (e.g. Chemistry), pres Ctrl+Shift+P and change the category in the Category combo and choose OK


You can use categories to influence where new elements are added with Add new
Branch selection does not affect the template used

Deleting category does not delete its elements

Task Extract adds elements to the current category (not the current tasklist)

For more see: Collection authoring FAQ

Branch selection does not affect the template used
Vidar Garlie, Norway, Mar 18, 1999)

When I go to the contents window, select a category branch and press Alt+A, the template of this category is not used! Can you help?
To use a category template, you have to first choose the category in the category combo box on the Tools toolbar. Selecting branches in the contents window does not affect the current category selection

Deleting category does not delete its elements
(Luis Gustavo, Brazil, Oct 1, 2000)

If I delete a category, will all its elements be deleted?
No. The category is an abstract structure living above the level of the knowledge tree. Once you delete it, no elements will be affected. Nor will the structure of the knowledge tree. To delete the section of the knowledge tree belonging to a category, select the root branch in the contents window and press Del

Task Extract adds elements to the current category (not the current tasklist) 
When I use Task Extract it adds tasks to a wrong branch in the contents window
Task Extract
adds tasks to the current category which may differ from the category in which the current tasklist is located

You can use categories to influence where new elements are added with Add new
(R.K., Sun, Jun 17, 2001 17:54)
I would expect SuperMemo to add a new item as a straight neighbor of the previously added element in the contents window. Why isn't it so?
Selection in the contents window is too transient to be the basis of choosing the insertion point for new material. This would require constant user attention as to the present selection. As a remedy, the concept of a category has been introduced. Each category, such as biology or geography, has its own insertion point called a hook. Now, all you have to do is to select a category, and Add new will add new elements to that category. Added elements will be listed sequentially as neighbors