United by a shared unease about China’s growing maritime assertiveness, Manila and Tokyo have pledged to build on the substantial advances of recent years.

Japanese Prime Minister Shigeru Ishiba has arrived in the Philippines to further boost an alliance in the face of China’s growing assertiveness in the region and he plans to symbolically board a Japan-built Philippine patrol ship that has repeatedly clashed with the Chinese coast guard.

The leaders of Japan and the Philippines agreed Tuesday on the start of discussions to pave the way for key security pacts, aiming t