The Morse code tree: a faster way to read a Morse chart
The Morse code tree is a chart sorted by sound instead of by alphabet. You start at the top, move left for every dit and right for every dah, and stop when the character ends: the letter you are standing on is the answer. Any letter takes at most four steps and any figure five, which makes the tree much quicker than scanning an A to Z chart for a pattern. It is a lookup tool for written Morse, though, and not a way to learn the code by ear.
How the tree is laid out
Picture a start point at the top with nothing in it. A dit takes you down and to the left, a dah down and to the right. Every spot in the tree is reached by exactly one path, and the path is the code.
Rather than a drawing, here is the tree as a table. Find the letter you are on in the first column, then move to the dit or dah column depending on the next element you read.
| From | Dit (go left) | Dah (go right) |
|---|---|---|
| Start | E | T |
| E | I | A |
| T | N | M |
| I | S | U |
| A | R | W |
| N | D | K |
| M | G | O |
| S | H | V |
| U | F | (no letter) |
| R | L | (no letter) |
| W | P | J |
| D | B | X |
| K | C | Y |
| G | Z | Q |
| O | (no letter) | (no letter) |
Read it as four levels. The first level holds the one-element letters, E and T. The second holds the two-element letters, I, A, N and M. The third holds S, U, R, W, D, K, G and O. The fourth holds the twelve four-element letters, with four empty spots that hold none of the 26 letters: ..--, .-.-, ---. and ----.
Two things fall out of the layout. Every letter on the left half starts with a dit and every letter on the right half starts with a dah. And if you flip the tree left to right, every dit becomes a dah: E swaps with T, A with N, S with O, U with G, R with K and W with D. Those mirror positions are the pairs whose codes are exact opposites.
Walking the tree: two examples
Take -.-. --- -.. . and decode it one character at a time. The spaces tell you where each character ends.
-.-.: dah to T, dit to N, dah to K, dit to C. The character ends, so it is C.---: dah to T, dah to M, dah to O. O.-..: dah to T, dit to N, dit to D. D..: dit to E. E.
The message is CODE. Now try .-- .. .-. .:
.--: dit to E, dah to A, dah to W. W...: dit to E, dit to I. I..-.: dit to E, dah to A, dit to R. R..: E.
That one spells WIRE. After a few words you stop reading the table and start seeing the turns: three dahs is always O, four dits always H. For a longer worked method, including how to handle messy notation, see how to decode Morse code by hand.
The figures on the fifth level
Figures are five elements each, so they hang one level below the letters. Four of them, 2, 8, 9 and 0, sit under empty spots, which is why a drawn tree keeps those spots even though no letter lives there.
| Figure | Code | Hangs under |
|---|---|---|
| 1 | .---- |
J, .--- |
| 2 | ..--- |
the empty spot ..-- below U |
| 3 | ...-- |
V, ...- |
| 4 | ....- |
H, ...., going right |
| 5 | ..... |
H, ...., going left |
| 6 | -.... |
B, -... |
| 7 | --... |
Z, --.. |
| 8 | ---.. |
the empty spot ---. below O |
| 9 | ----. |
the empty spot ---- below O |
| 0 | ----- |
the empty spot ---- below O |
So 1 to 5 all live on the dit side of the tree and 6 to 0 on the dah side, which matches the pattern of the figures: 1 to 5 start with dits, 6 to 0 with dahs. Morse code numbers 0 to 9 shows how to work any figure out without a chart at all. Punctuation sits on the fifth and sixth levels, beside and below the figures (the plus sign, .-.-., hangs under the empty spot .-.-), so a tree you draw by hand can stop at the figures.
Why it beats an A to Z chart, and when it does not
An alphabetical chart is sorted by letter. To decode --.- with one, you scan down the list comparing patterns until one matches, and with 26 rows of similar dots and dashes, it is easy to skip the right one. The tree is sorted by code, so you never search: each element tells you which way to turn, and four turns at most land you on the letter, here Q.
The tree has two limits.
It is slow the other way. To encode, going from a letter to its code, you have to find the letter in the tree and then trace its path back up. An alphabetical chart is faster for that job. Use the tree to read Morse and the A to Z chart to write it.
It needs to know where each character ends. The tree assumes you know when to stop walking. Written Morse with no spaces between characters is ambiguous: ... could be S, or E then I, or I then E, or three Es, and the tree cannot tell you which. Good written Morse puts one space between characters and a slash between words, as described in how to write Morse code in text. In sound, the same job is done by the gap of three units between letters.
Drawing it on scrap paper
For a puzzle or a treasure hunt, you can draw the tree from memory in a minute or two. Only the rows need remembering:
- E T
- I A N M
- S U R W D K G O
- H V F, a blank, L, a blank, P J B X C Y Z Q, two blanks
Write each row under the one above, two children under each parent, the left one for a dit and the right one for a dah. The third row, SURWDKGO, and the fourth, with its blanks, are the ones worth saying aloud a few times; the first two take care of themselves.
Why the tree will not teach you to hear Morse
The tree is a visual lookup, and that is exactly why it fails as a way to learn by ear. Walking it means making a decision for every element: left, right, left. At 20 WPM a dit lasts 60 milliseconds, and C, -.-., is over in 660 ms. There is no time to picture a tree and walk four turns while the next letter is already sounding.
Worse, practicing with the tree trains you to process Morse one element at a time, a habit that tends to hold learners back. A fluent listener does not hear dah, dit, dah, dit and then work out C. They hear the whole rhythm, dah-di-dah-dit, and it simply is C, the way a spoken word is a word and not a list of sounds. Learn Morse code by sound, not from a chart explains how to build that from the start.
So use the tree the way you would use a dictionary: for written Morse, for checking, for a puzzle. Keep it away from your listening practice.
If you have a page of dots and dashes to read on a Mac, Dot & Dash can do the walking for you. Its Morse to Text view reads typed or pasted Morse, characters split by spaces and words by a slash, and the message appears as you go. Its Reference lists the letters, figures, punctuation and prosigns, and resting the pointer on a character plays it, so you hear the letter you just looked up.
Questions
How do you read a Morse code tree?
Start at the top. For each dit move down to the left, for each dah move down to the right, and stop when the character ends. The letter you stop on is the decoded character.
Why are there empty spots in the Morse code tree?
There are sixteen four-element patterns but only twelve letters left after the fourteen shorter codes, so four patterns, ..--, .-.-, ---. and ----, hold none of the letters A to Z. Figures and punctuation hang below them: 2 under ..--, the plus sign under .-.-, 8 under ---., and 9 and 0 under ----.
Can I learn Morse code from the tree?
You can memorize the code from it, but it will not teach you to hear Morse. It trains element-by-element lookup, and at real speeds a letter is over before you can walk the tree.
Is the tree better than an alphabetical chart?
For decoding, yes, because each dit or dah tells you which way to go. For encoding a letter into Morse, the alphabetical chart is quicker.