Which country was designated to chair the 2019 summit of the Association of Southeast Asian Nations (ASEAN)?

Introduction / Context:
The Association of Southeast Asian Nations (ASEAN) is a regional organisation of Southeast Asian countries that works together on political, economic and security issues. The chairmanship of ASEAN rotates annually among its member states, and the chairing country hosts the main ASEAN summit and related meetings for that year. General knowledge and international relations questions often ask which country chaired ASEAN in a particular year. This question focuses on the chair for the year 2019.

Given Data / Assumptions:
- The year in question is 2019.
- The focus is on which country chaired the ASEAN summit that year.
- Options are Japan, Singapore, China and Thailand.
- Only ASEAN member states can chair ASEAN; dialogue partners cannot hold the rotating chair.

Concept / Approach:
ASEAN consists of ten member states: Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. The chair rotates each year among these members in a predefined order. Singapore chaired ASEAN in 2018. In 2019, the chairmanship passed to Thailand, which hosted the main ASEAN summits and related meetings. Japan and China are important dialogue partners of ASEAN but are not members and therefore do not chair ASEAN. Consequently, Thailand is the correct answer to this question.

Step-by-Step Solution:
Step 1: Recall that only ASEAN member states can chair the organisation.
Step 2: Strike out Japan and China immediately, because they are not ASEAN members; they are external partners.
Step 3: Remember that Singapore chaired ASEAN in 2018 and that the chairmanship rotates annually.
Step 4: Identify that in 2019 the chair was Thailand, which hosted the ASEAN meetings that year.
Step 5: Select “Thailand” as the correct option.

Verification / Alternative check:
Current affairs summaries often list ASEAN chairs year by year. Such tables show that Singapore held the chair in 2018 and Thailand in 2019, followed by other members in subsequent years. News headlines around 2019 ASEAN summits also referred to “Thailand as ASEAN chair” and highlighted Bangkok and other Thai cities as venues for key meetings. Recalling these facts confirms that Thailand was the chair in 2019.

Why Other Options Are Wrong:
- Japan: A major partner and participant in ASEAN related forums, but not a member of ASEAN, so it cannot chair the organisation.
- Singapore: Did serve as ASEAN chair, but that was in 2018, not in 2019.
- China: Also an important dialogue partner but not an ASEAN member, so it cannot hold the rotating chairmanship.

Common Pitfalls:
Some candidates know that Singapore has served as chair and might mistakenly choose it for 2019 if they forget the exact year. Others may not recall that only member states can chair ASEAN and might consider Japan or China because of their strong presence in regional meetings. To avoid these mistakes, learners should memorise the basic ASEAN membership list and remember that the chair rotates only among these ten countries. Associating the sequence “Singapore 2018, Thailand 2019” is a simple memory aid for this specific question.

Final Answer:
The country that chaired the ASEAN summit in 2019 was Thailand.