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, Invention and Slayer are currently the only three 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 120,000.
The amount of experience required to achieve true skill mastery in any non-elite skill 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 its own unique experience curve. The amount of experience required to reach level 120 is 80,618,654 (23,654,513 less experience than Dungeoneering, Slayer 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, Invention, and Slayer master capes also have unique emotes, while other master capes share their emote with their skill cape counterpart.
Reaching the requirement gives the message: Well done! You've achieved 104,273,167 XP in [skill]! You can now purchase a Master Cape from the respective skill master.
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.
First Ironmen to achieve level 120
- There was once a glitch which, upon reaching level 115 Dungeoneering, would inform the player that they were level 120 on the hiscores.
- Only three true masteries, provided with the Dungeoneering master cape, Invention master cape, and Slayer master cape have a unique emote due to Dungeoneering, Invention, and Slayer continuing up to level 120. The other skills have a virtual level, and the skillcape emote remains unchanged at the virtual level 120 in those skills.
- With the release of virtual levelling, players now have the ability to display all of their skills up to the maximum of 120, and up to level 150 with Invention. This offers no in-game benefits, with the exception of giving an increased chance of receiving a skilling pet. The maximum total virtual level (having every skill at 120, and Invention at 150) is 3270.
- On 14 March 2016, the message received upon achieving true skill mastery was changed to specify the skill rather than the generic "this skill".