The B button on various controllers. From left to right, top to bottom: Nintendo 64 controller, GameCube controller, Wii Remote, Classic Controller, Nintendo 3DS, Wii U GamePad, the Joy-Con, and the Switch Pro Controller

The B button is either the large, green button on the Nintendo 64 controller, the small, red button on the Nintendo GameCube controller, the rectangular trigger button on the back of the Wii Remote, the clear button towards the bottom right of the Classic Controller, the circular button on the Wii U GamePad, Wii U Pro Controller and Nintendo 3DS (varies in color on 3DS, matches the color of the Wii Remote, Wii U GamePad and Wii U Pro Controller), or the bottom dark gray face button on the Nintendo Switch's right Joy-Con and Pro Controller.

Overview

In the default controller layouts of all installments in the Super Smash Bros. series, the B button is used mostly for executing special moves. This includes neutral specials, side specials, up specials, down specials, Final Smashes and some command-input moves. Outside of gameplay, the B button is also the standard "back" button when navigating menus.

When playing with the Wii Remote held sideways, the 1 button acts as a substitute for the B button, performing special moves, whereas the actual B button is used to shield the character with default controls. When using Joy-Con (R) as a single Joy-Con held horizontally, the B button will become the left button, acting like a Y button and performing jumps, while the B button's menu and battle functionalities are given to the A button.

Super Smash Bros. Brawl introduced the controls menu option introduced in this game allows non-default actions to be mapped to the B button. This option has returned in every subsequent Smash release. While not directly related, Nintendo Switch system version 10.0.0 introduced the ability to map the functionality of any button to any other button from the console options menu, further diversifying how the B button can be used in Ultimate.

Controllers and buttons
Nintendo 64 controller
Nintendo GameCube controller
Wii Remote (and Nunchuk)
Classic Controller	LR
Nintendo 3DS
Wii U GamePad / Wii U Pro Controller	LR
Joy-Con / Joy-Con 2	/ GL button GR button
Nintendo Switch Pro Controller / Nintendo Switch 2 Pro Controller	LR / GL button GR button
Third-party controllers	Hori Mini Pad · Arcade controller · Keyboard
Other	Controls · Smash Controller · Controller modification

• Controller buttons
• Game controls