Official Reference Documentation for The Curtiss Annotation Nomenclature (C.A.N.) System
CAN Travel Codes exist because reading happens in imperfect, unstable conditions. Mark what matters in the moment. Complete the annotation when you’re able. Once converted, CAN Travel Codes disappear—leaving only the finished CAN Annotation behind.
| Mark | Name | When to Use |
|---|---|---|
[ ] |
Brackets | Multi-line passages (convert to underlines later) |
• |
Dot | Quick generic flag to mark that something matters here |
|, ||, ||| |
Vertical Line(s) | Flag and rate importance (1-3 levels), with 3 being most important |
CAN Travel Codes are temporary, simple marks for annotating physical books when you can’t write cleanly—on buses, trains, or as a passenger. They let you capture insights in the moment without ruining your margins with crooked underlines.
The workflow is simple:
CAN Travel Codes aren’t a separate system—they’re incomplete CAN Annotations waiting to be completed and erased. Once you convert them, no trace remains.
CAN Travel Codes are for hand-annotating physical books with pencil (or an easily erasable writing item). Digital tools always offer precision, so there’s no need for CAN Travel Codes there. As a result, CAN Travel Codes won’t be included in any software implementations.
CAN Travel Codes are intentionally ambiguous—they mark that something matters, but not its category. Was it a definition? A key concept? A thematic statement? That’s what the CAN Code adds during conversion. The ambiguity of the CAN Travel Code is both its strength (fast, low-commitment marking) and its limitation (harder to categorize later). All CAN Travel Codes are erased during conversion. They are temporary shadows that vanish once you add the proper CAN Code and complete the CAN Annotation. The examples below show one possible conversion, but yours will depend on what you intended and what you remember when you return to the passage.
Brackets: [ ]
Mark multi-line passages without underlining. Draw brackets around the text—they survive bumps better than underlines. During conversion, erase the brackets and underline the passage instead.
Example conversion: [ passage ] might become (RA), (T), (KC)*, or something else entirely.
Dot: •
The fastest mark—one pencil touch when you just need to flag something for later.
Example conversion: • might become (D), (T), (!), or whichever CAN Code that fits when you remember and/or re-read the passage.
Vertical Line(s): |, ||, |||
Flag and rate importance without categorizing it yet: one line = worth noting, two = really important, three = extremely important. Since the Vertical Line(s) already flag the passage, combining them with the Dot is redundant.
Example conversion: || might become (KC)*, (T), (RA), etc.—the vertical lines tell you how important it is, not its category.
Trust your instincts. Any mark is better than losing the passage. Don’t overthink which code to use.
Default to the Dot if you’re unsure which Travel Code to use. It commits you to nothing except “this matters.”
Use pencil so you can erase and adjust during conversion.
One mark per passage — except Brackets, which can combine with the Vertical Line(s).
Complete the CAN Annotation as soon as you can — when travel stops, you reach a desk, or you’re ready to pause and reflect.
A CAN Travel Code is an incomplete CAN Annotation. It becomes a completed CAN Annotation only after you:
Until then, it’s an incomplete CAN Annotation—which is why the 24-hour guideline matters. Context fades fast. But once the CAN Annotation is complete, you’re good to go for years to come (or until you re-read it)!
On the bus (8:30 AM): A passage about resistance tactics strikes you. Bus is hitting bumps. You draw brackets [ ] around the passage—takes a second, stays clean.
Still on the bus (8:45 AM): You come across another passage with a definition that seems important. Bus crosses railroad tracks. You make a dot (•) in the margin.
Later that morning (10:00 AM): You sit down with the book. You erase the brackets, underline the passage, and add (RA)* in the margin for the first passage. For the second passage, you erase the dot and it becomes (D). Both conversions take under a minute.
Result: Insights captured during travel, converted while still fresh. The CAN Travel Codes are gone—only clean, complete CAN Annotations remain. You’d never know they were used.
Are CAN Travel Codes a separate system?
No. They’re incomplete CAN Annotations—temporary marks that are erased and replaced with proper CAN Annotations during conversion. Once converted, they leave no trace.
Why can’t I circle them?
Circles in CAN mean completion. CAN Travel Codes aren’t completed. The visual distinction helps you track what still needs attention.
Why only 3 codes?
More CAN Travel Codes = more decisions during bumpy conditions. These 3 cover all essential functions with minimal cognitive overhead.
Can I combine CAN Travel Codes?
Brackets can pair with Vertical Line(s) (e.g., brackets around text plus || in the margin). But Brackets and the Dot (together, for the same passage) are redundant—both just say “this matters.” And Dot + Vertical Line(s) are redundant—Vertical Line(s) already flag the passage.
Can I create custom CAN Travel Codes?
We highly recommend against it. Standardization is what makes your marks recognizable weeks later. Use a dot and sort out specifics during conversion.
What if I can’t convert within 24 hours?
Convert when you can. Some preserved insight is better than none. The 24-hour guideline exists because reading memories fade quickly—it’s a strong recommendation, not a rule.
Can I use CAN Travel Codes at home?
If you’re stable, use proper CAN Codes. CAN Travel Codes exist for unstable conditions. Using them at your desk adds unnecessary steps.
What about disagreement while traveling?
Mark with a Dot or Vertical Line(s), then convert to (X) when stable. Don’t invent new Travel Codes—the categorization happens during conversion.
Appropriate:
Not appropriate:
Simple test: If bumps would ruin your underlining, use CAN Travel Codes. Otherwise, use standard CAN Codes.
CAN Travel Codes are part of the CAN ecosystem but documented separately from the core guide/specification. Three reasons:
Scope. CAN Travel Codes apply only to physical books during unstable conditions. The specification defines the CAN Annotation system itself—CAN Travel Codes are a capture nomenclature for a subset of use cases.
Output. CAN Travel Codes are incomplete CAN Annotations. They are to be erased and converted to a (properly formatted) standard CAN Code, producing a completed CAN Annotation. The specification need only define the final annotation types.
Universality. The specification should contain what all users need. Users annotating digitally or in stable environments experience little gain from CAN Travel Code documentation.
CAN Travel Codes remain supplementary guidance for the specific situations described above.