Scrum in rugby is an ordered formation of players, in which the forwards of a team push forward against a similar group from the opposing side. An agile practice borrowed this term and now it is widely used project management which emphasizes daily communication and the flexible review of plans that are carried out in short, iterative phases of work.

Understand Scrum basic concepts in three minutes by watching this video  HERE.

The Scrum Master role, the legend of Scrum, is part of the Scrum framework and does not have any real authority, but performs a servant leadership. The responsibilities of a Scrum Master usually include:

• Removing impediments
• Improving interactions between the team and product owner as well as others outside the team
• Coaching the team and practicing agility
• Facilitating team meetings
• and etc.

Certifications and training on the role of Scrum Master are available and valued. The Licensed Scrum Master (LSM), Certified Scrum Master (CSM) and Professional Scrum Master (PSM) are reputable Scrum Master Certifications. 

• The Licensed Scrum Master (LSM) certificate is by Scrum Inc. and its curriculum was developed by the co-creator of Scrum, Jeff Sutherland. 
• Certified Scrum Master (CSM) certificate is accredited by Scrum Alliance.
• Professional Scrum Master (PSM)   is accredited by Scrum.org.
  

The ABCs of the three are listed below.

Comparison of LSM, CSM, & PSM

	LSM	CSM	PSM
Certified By	Scrum Inc.	Scrum Alliance	Scrum.org
Workshop Required
Workshop Length	2-DAY	2-DAY	2-DAY
Workshop in-person/online
Exam Cost	USD1,000-1,400 (workshop included)	USD29	USD150
Open Book Exam
Exam Length	no limit	1-hour	1-hour
Passing Score	23/30	37/50	77/80
Valid Length	1 YEAR	2 YEARS	Permanent
Attempts	2	2	1
Renewal Cost	USD50/YEAR	USD50/2-YEAR	Permanent

Choose one based on your goal

There are more certification options out there, and you might ask yourself, " Which certification should I work on? " and "Which exam should I take?"

It is more about who you are and what you want to get from it. For example,

• As an executive, you should choose CSM, if you want to empathize with your staff and employee.
• As a manager, you should start with LSM, if you want to help your team solve problems with productivity, quality, and speed.

Generally speaking, the LSM passing rate is 75%, compared to CSM 74%. If you read and understand the Scrum Guide, with the project management experience you have, it should not be a big challenge for you to pass the exam. You should also bear in mind that learning is the ultimate goal and certification is just a certification. 

Reference

1.  https://www.berteig.com/scrum-master-certification-comparison/

2.  https://appliedframeworks.com/tips-for-taking-the-csm-exam/

3.  https://www.zentao.pm/blog/how-to-get-scrum-certified-scrum-master-249.html

4.  https://www.knowledgehut.com/blog/agile/scrum-master-certification-cost