Ryuu is a first name for boys.
Recently, the name Ryuu has been given only a handful of times a year and is therefore particularly rare, at least in the US. In recent years, not even one boy in 100,000 has been named Ryuu. That means that a boy named Ryuu is exceptional and may not meet another person with the same name his whole life.
Well, you might say, you probably figured that out yourself! But what you might not know is: The letter R is quite common as an initial letter for boys’ names. To be precise, 5.2% of all boys' names in the US begin with this letter. The most common first letters of boys' names, by the way, are J, A and D.
With four letters, the name Ryuu is shorter than most other given names. In fact, only 5.5% of all common first names in the US consist of exactly four letters. Just 1.2% of all first names are even shorter, while 93% consist of more than four letters. On average, first names in the US (not counting hyphenated names) are 6.5 letters long. There are no significant differences between boys' and girls' names.
Therefore: As 5.2% of all boys' names start with R, this initial letter occurs much more often than all 26 letters on average. And maybe interesting to know: of all the names that begin with an R, Robert is the most common.
If your name is Ryuu and someone asks after your name, you can of course just tell them what it is. But sometimes that isn't so easy - what if it's too loud, and you don't understand them well? Or what if the other person is so far away that you can see them but not hear them? In these situations, you can communicate your name in so many other ways: you call spell it, sign it, or even use a flag to wave it...
So that everyone really understands you when you have to spell the name Ryuu, you can simply say:
Braille is made up of dots, which the blind and visually impaired can feel to read words.
Just use American Sign Language!
These flags are used for maritime communication - each flag represents a letter.
In the navy, sailors of two ships might wave flags to each other to send messages. A sailor holds two flags in specific positions to represent different letters.
In Morse code, letters and other characters are represented only by a series of short and long tones. For example, a short tone followed by a long tone stands for the letter A. Ryuu sounds like this: