the narrow part of the peninsula, is it related to any war?
Yes, the Pacific war
Kra Isthmus
On 8 December 1941 local time, the Imperial Japanese army landed in Songkhla invading Thailand. 
who is considered as the sultanate of singora? It is a heavily fortified port city in southern Thailand. is there any tomb found there? Yes, the tomb of Sultan Sulaiman Shah. name any of its landmark? UNANSWERABLE did it get destroyed by anyone? Yes, by the East India Company was the above sultan the ruler of this city? UNANSWERABLE is any fort located here? Yes, the forts at Khao Daeng the place where this city is located, what is that place's geographic location? Southern Thailand is on the Malay Peninsula,bounded to the north by Kra Isthmus, the narrowest part of the peninsula. what language is spoken here? Central Thai
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Kra Isthmus [SEP] Pacific War
On 8 December 1941 local time, the Imperial Japanese army landed in Songkhla invading Thailand. Because of the International Date Line, this actually occurred hours before the 7 December (Hawaii time) attack on Pearl Harbor, making it the first major action of the Pacific War. The Japanese forces then moved south towards Perlis and Penang as part of the Malayan campaign which culminated in the capture of Singapore.