The last time I introduced you the greeting, “Good morning” in Japanese.  Do you still remember the word?  Yes, that’s “O-ha-yoh.”
Today you are going to learn greetings at night time. 

 There are two greetings in the evening; both are used after the sun goes down.

(1) Kon-ban-wa (Good evening)
 
“Good evening” in Japanese language is “Kon-ban-wa.”  It sounds similar to “Kon-ni-chi-wa”.
Both words end with “wa”. 
 
I don’t know the meaning of “wa”, but I know what “Kon-ban” and “Kon-ni-chi” mean.
 
・“Kon-ban” means tonight, and
・“Kon-ni-chi” is today.
They are general nouns, but when we add “wa” to those words, they change to greetings. 
 
“Kon-ban-wa” is formal as well as “Kon-ni-chi-wa”, and Japanese people use it only when you see acquaintances or seniors.  Among friends, we usually don’t say “kon-ban-wa”.
 
So, “Kon-ban-wa” is a formal greeting.  Then, what should we say when we see friends at night? 
 
Well, I don’t know an answer.  As well as “Kon-ni-chi-wa,” that depends on people. I usually call my friend’s name and start a conversation with “How have you been?” or something.
 
 
(2) O-ya-su-mi (Good night)
 
The second phrase for night is “good night.”  It is “o-ya-su-mi” or “o-ya-su-mi-na-sai.” The latter is a formal form. These are used only when you say “goodbye” to someone.
 
In southern California, people sometimes say “good night” instead of “goodbye,” when they get off work at 5p.m., but in Japan, we don’t say “o-ya-su-mi” in the situation. It sounds strange if I hear “o-ya-su-mi” in the office. Obviously, we don’t sleep at work.
 
“O-ya-su-mi” is used when we are going to bed. But, sometimes, some people use “o-ya-su-mi-na-sai” instead of “good-bye” when it is late at night.
 
It is 11p.m. now, so in this case, I will say to you, “o-ya-su-mi.”
 
Thanks for reading!