Hi Im traveling next month to Japan from NY on a cruise. I have a few questions: 1 the entire flight will be during daytime. Do i have to put on Tefilin again after crossing the dateline? 2. Any halacha regarding shabbat in Japan because of the dateline? 3 Can we eat salmon on the cruise if it is double wrapped before grilling Thanks so much

Shalom, Thank you for your questions. As you are probably aware, there are various opinions as to where the halachic dateline is, and even more varied opinions about the halachot of crossing it (wherever it may be). I rule here based on many standard opinions - 1) You have nothing to lose in putting tefillin on again – with a bracha. Every Jew is allowed to put Tefillin on several times in the same day, and in your case, according to one view, the “new date” obligates you again – so you can easily fulfill this opinion without entering into any doubt at all. In connection with davening again – it is a machloket, as to if the obligation is based on your experience of day / night, or based on the calander date. In my opinion, you do not have to daven the tefillot you have already davened again. (Some say you should “redaven” the last tefillah (shacharit or mincha) on condition that if you are not obligated then it is a free will prayer. You need not follow this opinion). 2) According to the Chazon Ish Shabbat in Japan is on Sunday. The majority of Rabbinic opinion holds it is on Saturday. You should follow this major opinion. (There are those who suggest being strict on Saturday night and Sunday not to do any Torah level melacha – I do not believe this is necessary). 3) Theoretically double wrapping a known kosher fish allows it to be cooked in a non-kosher oven. However on a practical level, you would have to supervise the wrapping and cooking, making sure that it was in fact completely and securely double wrapped at all times (this is achieved in airline meals by sealed containers that are only opened by the Jew at the time of eating). Additionally, you would need to use only kosher plates and silverware (or disposables). These practicalities might make it very difficult to have cooked fish on your trip. Perhaps try to pre-order sealed kosher meals. Have a wonderful trip, Blessings.