j

Synopsis:
j <channel>

Description:
j lets you join a new channel. If you are on multiple channels, the specified channel will become the current one. If you do not specify a channel (or channels) to join, your client will display your current channels, along with their respective modes and users, and which server you are on the channel from.

Examples:
To join channel blah (or create it if it does not exist):
/j blah

Aliases:
j is identical in operation to join.