For details of this event, read http://en.wikipedia.org/wiki/Mongol_invasions_of_Japan, esp the second invasion http://en.wikipedia.org/wiki/Mongol_invasions_of_Japan#Second_invasion_.281281.29 .
For use of Sapta-Naadi Chakra, see http://vedicastrology.wikidot.com/sapta-nadi-chakra
Now, use Kundalee Software's Medini mode and its Meru-WorldChart to analyze this important event which saved Japan from Mongol (Chinese) domination. Check horoscopes and SBC (Sarvato-Bhadra-Chakra) as well as SNC (Sapta-Naadi-Chakra) of D-1, D-27 and D-30, you will understand why the much stronger army of China could not defeat the weak Japanese army. Here is the example using D-27 which shows strength :-
Select "Medini" folder in Kundalee's data input page, then select "MeruWorldChart" in the top left combo of that page, then enter "1281" in the YEAR box on left side of that data innput page and click the "SHOW" button (if you want English, select it also in same input page). You will get D-1 chart as default. Then, in the SWITCHBOARD, click "MAIN" button, and then a new page will open in which enter "27" instead of "1" in the Divisionals box and then click "Divisionals" button in English mode or "Shodashvarga Dashaa" in Hindi mode, you will get D-27 charts.
Its SBC has following planets having vedha on "chi" (i.e., on the consonant "ch" and vowel short or long "i") :-
Moo-Sat-Sun-Mer on China's "chi".
Moo-Sat-Mar-Rah on Japan's "Ja" (consonant "J" and vowel "i").
Since Moon and Saturn are common to both China and Japan, we are left with the remaining planets which decide the outcome of war. Sun is bitter enemy of both China and Japan, but it has SBC-vedha on China only, hence China is harmed by inimical Sun, while Mercury is neutral. Sun is 8L (Lord of 8H or 8th house) and therefore malefic, while Mercury is mixed by dint of being 6L + 9L. Therefore, China is at a loss due to SBC vedha of Sun.
On the other hand, Japan has SBC-vedha by Mars and Rahu, Mars being friendly and Rahu being fast friendly. Moreover, Mars sits in killer house 8H (therefore, it kills enemies because it is friendly to Japan while 8L is inimical to China). Rahu is malefic, but being fast friend of the sign in which Japan is situated, Rahu fails to harm Japan.
Then, we check the SNC (Sapta-Naadi-Chakra) to find out the reasons behind the Typhoon which saved Japan from slavery. SBC planet Sun was in Vaata and Mercury was in ChanDaa naadi, hence causing fierce winds which were harmful for China due to SBC vedha and enmity of Sun. On the other hand, Mars which was friendly to Japan in SBC vedha was in Jala Naadi and therefore Japan was helped by Waters. Hence, Fierce Winds and Waters helped Japan to win the war in spite of having a very weak army and navy.
Check D-1 and D-30 also to find out casualties and other aspects of the war.