Why is Mew numbered 151?


Mewtwo is the clone of Mew. This means that Mew existed before Mewtwo.

So why is Mew numbed 151 in the Pokedex and Mewtwo 150?




Because Mew wasn't intended to be one of the 150 pokemon you can acquire
through normal gameplay. It was the "mystery" Pokemon, no one was supposed to
know its existence. It was only attainable by

  * Nintendo events
  * Gameshark
  * Game glitch

So yeah it makes no sense, but, if Mewtwo had been #151, your Pokedex in Red
and Blue would have a gaping hole in it at #150.

Mew was considered extinct when the Pokedex was made. But as Mewtwo was alive
and known, he was placed first. Later, Mew's resurrection of his species in
Emerald by a scientist meant they could now get his info for the Pokedex.
Mew's original form in the Pokedex was actually just "???" Pokemon, who could
learn any move.




Let us be reminded that the Pokemon franchise started off from video game, and
its initial release was [Pokemon Red and
Green](http://en.wikipedia.org/wiki/Pok%C3%A9mon_Red_and_Blue) in Japan in
1996. So Mew's very first appearance can only be in Japanese Pokemon Red and
Green.

According to Bulbapedia, in the [Trivia section of
Mew](http://bulbapedia.bulbagarden.net/wiki/Mew_%28Pok%C3%A9mon%29#Trivia):

>   * Mew was a little-known secret when Pokémon Red and Green were first
> released in Japan. Even Nintendo was not initially aware that Shigeki
> Morimoto had programmed it into the game.
>
>   * In an interview with Game Freak and Creatures, Inc. in [Nintendo
> Power](http://bulbapedia.bulbagarden.net/wiki/Nintendo_Power) issue 134,
> Shigeki Morimoto revealed that he created Mew two weeks before game
> development was finished.
>
>

Quoting from [the interview](http://www.nintendo.co.uk/Iwata-Asks/Iwata-Asks-
Pokemon-HeartGold-Version-SoulSilver-Version/Iwata-Asks-Pokemon-HeartGold-
Version-SoulSilver-Version/1-Just-Making-The-Last-Train/1-Just-Making-The-
Last-Train-225842.html) which is cited in the Bulbapedia page:

> **Morimoto:** We put Mew in right at the very end. The cartridge was really
> full and there wasn’t room for much more on there. Then the debug features
> which weren't going to be included in the final version of the game were
> removed, creating a miniscule 300 bytes of free space. So we thought that we
> could slot Mew in there. What we did would be unthinkable nowadays!
>
> **Ishihara:** This is in spite of being told after debug ended that you
> weren’t to tamper with even a single bit! (laughs wryly)
>
> **Iwata:** What’s the point of going through all the trouble of the debug
> process if you’re going to go and fiddle with the game afterwards…? I’d
> venture that this all came from Morimoto-san’s mischievous nature.
>
> **Morimoto:** Well, it was a prank that everyone right up to Tajiri-san was
> in on. But even though Mew was in there…
>
> **Iwata:** …It wasn't actually supposed to appear in the game, right?
>
> **Morimoto:** Right. Unless we could think about any good opportunity to do
> so, the existence of Mew wouldn’t have been revealed to the public. It was
> left in there in case it was suitable for some post-launch activity. But if
> there wasn’t anyone among ourselves who wanted to use it, I thought it would
> be fine to just leave it as it was.
>
> **Iwata:** Mew could very well have ended up never appearing in the game.
>
> **Morimoto:** Right. But then due to an unforeseen bug, Mew ended up
> appearing in some players’ games. It looked like we planned all of this, but
> that wasn’t the case. So although it caused all sorts of problems to many
> concerned, fortunately enough it ended up having a positive effect.
>
> [...]
>
> **Iwata:** That’s how the “Legendary Pokémon Offer”8 came about.
>
> 8 The “Legendary Pokémon Offer” was announced in the April 1996 edition of
> CoroCoro Comic. Twenty winners would be selected who could send their game
> cartridge in so that the Mew data would be uploaded onto it. There were
> approximately 78,000 entrants.

From the quotes above, it is evident that Mew was not supposed to appear in
the first generation. It was only programmed in at the last minute, occupying
the space of debug feature.

The interview hinted at the fact that Mew was added after the debug process
had ended, so swapping the number of Mewtwo and Mew at that point would have
been disastrous, since Mewtwo had an event in the Cerulean Cave, and its
stats, move set, flavor text, ... record would have to be swapped with Mew's.
Appending a record at the end was safer, especially when the record was not
supposed to be used at all during the normal game play.

