A cap (キャップ, kyappu), or capcode, is a unique identifier that's used on some bulletin boards. It was introduced to 2channel in late 1999 and dubbed a “cap” since Hiroyuki saw that “bōshi” (機能, lit. “feature”)¹⁾ was a homophone with “bōshi” (帽子, lit. “hat”).

These identifiers are mostly given to those who have a role on a board or the entire website, but they used to be handed to named regulars in the early days of 2channel before the trip (one-person cap) was introduced in August 2001. In some instances, they may also given to notable people.

The traditional method requires the user to input a special string in the email field of the post form and the name would change accordingly in the submitted post. On certain boards like 2channel and Shitaraba, it results in the designated name with a star (★) and to prevent spoofing, the star becomes an empty star (☆) when used in the name field. However, some boards and scripts use different methods.

On 2channel, the aforementioned traditional method is used since they did invent caps, and it's suggested that they still use this method considering that the Cap Stopper also utilizes the email field.

“fusianasan” was a cap password used by 2channel's founder, Hiroyuki Nishimura, but this was leaked on September 23, 1999. The damage was reverted and attempting to use it would result in your host name being displayed. It'd later become a way to trick newcomers into showing their host name, but there are other methods. This trick was allegedly discontinued in late 2017.

• Strong Power (強権, Kyōken)
• Developer (開発, Kaihatsu)
• Setting Changer (設定変更人, Settei Henkō-jin)
• “Restorer” (復帰人, Fukki-jin)
• Deleter (削除人, Sakujo-jin)
• Rock Corps (Rock部隊, Rokku Butai)
• Scorch Corps (焼部隊, Shō Butai)
• Reporter (報告人, Hōkoku-jin) - A cap that reports content to be regulated.
• Canceler (解除人, Kaijo-jin)
• Guide (案内人, Annai-jin)
• News Reporter (記者, Kisha) - A cap, given in /newsplus/-style boards.
• BE Icon Manager (BEアイコン管理, Bī Aikon Kanri)
• Others

The cap stopper (キャップストッパー, kyappu sutoppā) is a 2channel feature where users input “#DEL:” followed by someone's cap password in the email field to kill a leaked cap and further use will result in an error message saying that you cannot use your cap on the server. This feature was implemented late 2014,²⁾ and users are encouraged to use this feature.

On Shitaraba, the same traditional method is also used, but called a “handle password” (ハンドルパスワード, handoru pasuwādo) instead of a “cap” and not much else is known due to their foreign IP ban.

On 4chan, the use of caps are restricted to logged-in registered users who input “pubies” in the email field according to a 2010 leak,³⁾ though it's possible that this might've changed. This results in a colored name and a variant of the 4chan icon if the user is apart of Team 4chan which is almost always the case. The tooltip states the obvious if they're apart of Team 4chan, but shows a member's ID instead on 4chan's /j/ board.

• Anonymous ## Founder - This capcode is supposed to be used by Christopher Poole (moot) but it hasn't been used yet. In his final 4chan Q&A, he called it the “Admin Emeritus” capcode.
• Anonymous ## Admin - This capcode is used by the administrator, “hiroyuki”, and those who manage to hack into the 4chan administration panel. In the past, this was primarily used by “moot”.
• Anonymous ## Manager - This capcode might've been restricted to /j/,⁴⁾ but was first spotted outside of it in /qa/ around 2016. It seems like they can fire moderators and rogue janitors.
• Anonymous ## Mod - This capcode is used by mods that perform site maintenance (e.g. delete/ban on all boards, sticky/close/autosage threads, etc.). They should not be confused with janitors.
• Anonymous ## Developer - This capcode is given to developers who are involved with developing the proprietary software, Yotsuba, and were first spotten on August 8, 2012 in /q/.
  • Anonymous ## BlOgGeR - In the leaked source code, this capcode was for Randall Munroe of xkcd, who would have to input “munroexkcd” in the email field.
• Anonymous ## Verified - This capcode is granted to notable people unaffiliated with “Team 4chan” and it has been actively used by “Tattun” in recent years.
  • Anonymous ## Verified - This capcode might be an early variant of the “Verified” capcode, used by Andrew W.K. and Deadmau5 in 2011.

For boards that use Tinyboard, Vichan, or its derivatives, caps work very similar to tripcodes, but only work when logged in. In the name field, input ## Admin to get ## Admin and ## Mod to get ## Mod. If you don't have the proper permissions, it spits out a secure tripcode. It should also be noted that administrators are not bound to the ## Admin cap and may use custom caps like ## God or what have you.

• ★ on 2channel's Wiki
• Cap (Electronic Bulletin Board) on Japanese Wikipedia
• Cap (Electronic Bulletin Board) on Niconico Encyclopedia