<p>About 60 vessels and 400 planes from the two countries' armed forces were taking part in the exercises in the Sea of Japan and near Okinawa island, which come two days after a joint drill between the US and South Korea ended.<br /><br />The South Korean defence ministry has dispatched observers to the drills for the first time. Japan sent observers to US-South Korean exercises in July. North Korea Nov 23 shelled Yeonpyeong island, near the disputed border between the Koreas in the Yellow Sea, killing two marines and two civilians.</p>
<p>About 60 vessels and 400 planes from the two countries' armed forces were taking part in the exercises in the Sea of Japan and near Okinawa island, which come two days after a joint drill between the US and South Korea ended.<br /><br />The South Korean defence ministry has dispatched observers to the drills for the first time. Japan sent observers to US-South Korean exercises in July. North Korea Nov 23 shelled Yeonpyeong island, near the disputed border between the Koreas in the Yellow Sea, killing two marines and two civilians.</p>