Singapore's large defensive perimeter differed from the narrower maritime approaches around it. Minefields and submarines could have exploited parts of that geography to restrict an attacker. Useful positions lay far apart and required forces to cover them. The same geography created both strategic value and a severe concentration problem.
Notable Point · 5:59-6:21
Malaya's approaches offered defensive possibilities
Singapore was difficult to defend as a whole, but its maritime approaches included channels where minefields and submarines could complicate an attack.