True skill mastery

True skill mastery is an achievement greater than skill mastery, obtainable by reaching level 120 in any skill. The achievement was first released on 12 April 2010 with the Dungeoneering skill and later expanded when master capes were released for other skills on 28 April 2014.

Once a player reaches level 99 in a skill, they may continue training to level 120 and receive a Master cape of Accomplishment. Dungeoneering and recently released Invention are currently the only two skills that have levels past 99 up to 120. True skill mastery for other skills is achieved when the virtual experience requirement for level 120 is met. The capes can be bought from the existing skill cape sellers for.

The amount of experience required to unlock level 120 Dungeoneering or virtual true skill mastery in other skills (not including Invention) is 104,273,167. This is about eight times the experience needed to reach level 99 on a normal experience curve.

Invention, as an elite skill, has it's own unique experience curve. The amount of experience required to reach level 120 is 80,618,654 (23,654,513 less experience than Dungeoneering or virtual level 120 in other skills).

Master capes look different from an ordinary level 99 skill cape: the skill symbol is located lower than on an ordinary skill cape, with particle smoke emitting from the bottom of the cape. The Dungeoneering and Invention master capes also have unique emotes while other master capes share their emote with their skill cape counterpart.

Reaching the requirement gives the message:

The maximum total virtual level (having every skill at 120) is 3240.

History
Jagex polled players about plans to add Master capes to all skills. The poll won with 63% of the votes. On 28 April 2014 the Master cape of Accomplishment was released. These capes are awarded for reaching the experience needed for level 120, which is 104,273,167. Skill levels are not increased accordingly, and the Master capes do not have their own emotes.

Trivia

 * There was once a glitch which, upon reaching level 115 Dungeoneering, would inform the player that they were level 120 on the hiscores.
 * Only one true mastery, provided with the Dungeoneering master cape, has an emote due to Dungeoneering continuing up to level 120. The other skills have a virtual level.
 * With the release of virtual levelling, players now have the ability to display all of their skills up to the maximum of 120. This offers no in-game benefits.