Why do you use は for Konnichiwa (こんにちは) instead of わ

Many people who started learning Japanese are confused when they found out that the famous Japanese greeting, Konnichiwa, is end with は (ha) not わ (wa).

First of all, no it is not a misprinted on your book, it’s truly は.
In fact, you will also find out later on that Konbanwa which means good night, is also end with the exact same は.

But Why??

It doesn’t make sense at first, but it’s quite logical if you have learned about Topic marker particle .
In case that you haven’t, we recommend you to read this lessons here Topic Marker particle は.

So… the confusing は is actually a particle. In this case, as a particle, it is read as WA, not HA.

Aha!… But there is no continuation after は…

Yes, because it’s actually the contracted version of the real lengthy sentence!!
They are actually an abbreviation (a lazy version) of a long sentence. “Konnichi wa gokiken ikaga desu ka?” which means “How are you feeling today?”. so the KON NICCHI means “This day” while the は is actually being used as particle in that sentence. In the case of KONBANWA, KON BAN meaning “This night/evening”.

Long story short, time passes and the polite long sentence is being abbreviated into just KON NICHI WA and KON BAN WA.Literally, you could say Konnichiwa / Konbanwa is like saying “How is your day/night?”. But in this modern era, the usage has become more or less similar to “Hello/Good Evening/Good night”.

We hope this helps clear things up. For a more complete explanation, you could check this article about why sometimes は is read as WA

Have a great day! ｡ﾟ✶ฺ.ヽ(*´∀`*)ﾉ.✶ฺﾟ｡