SUSHI
Toro - fatty tuna
Very expensive, but very good. Beware: cheaper restaurants that advertize this on the menu, but it is usually not real O-toro. Real O-toro will run about $10-12 per 2 piece order. Few places offer it because of its price. If it's too expensive, not too many people will buy it, hence they may end up throwing some away - which is heart and bank-breaking.
Emgawa - flounder fin
This is really good. It has a texture of like nothing else I've have - chewy, but crunchy, but soft. This is rare, as well, mainly because not too many people are into it. Like many of the rare pieces, you usually won't see it on the menu, you should ask the chef if they have it.
Iwashi (or iwasi) - sardine
These are not the ones in the can. They're fresh and they're raw. Not very popular among greenhorns, so not as prevelant as say... salmon. The chef is any good, he'll put a small amount of fresh grated ginger and green onion in the middle of "X" to help balance the strong flavor.
Aji - horse mackerel
This is one of my favorites. It, too, is accompanied by the ginger/scallion on top. Aji is related to the popular and ever-prevelant saba (mackerel), but very different in taste. Saba is marinated in vinegar and has a strong fishy taste that some either love or hate. Aji has a faint taste of fish, but has a much softer texture. This is rather rare, but not as rare as real O-toro.
Jeff (the chef downstairs) will have a special order of Aji every once in a while - $10 - he fillets a whole aji (which is about 9-10") and serves they sashimi slices over the fish's body, garnished with radish etc.
Oshi Sushi
This is a style of sushi most commonly seen with saba (mackerel) and unagi (fresh water eel: seen far right). Oshi sushi was the first style sushi ever. Layer vinegared rice, then fish or some other topping, then more rice. Put a heavy stone on top and weigh it down. Remove the rock and slice into bite-sized pieces. This style of sushi last longer than what we Americans are accustomed to call sushi because the pressing forces out all the excess air inbetween the rice etc.
Some places do this, some don't - but you always have to ask for it. Back in the day, they'd press their sushi for a long time under very heavy weight. If you were to get this now, it would be pressed quickly under lighter pressure, just so that you'd get an idea of the shape and size. I've never had real oshi sushi.
Whale
I've never had this, but I would in a heart beat if I could. It's illegal in the US (and most everywhere else except Japan), but I've heard stories of people having it in the DC area at certain un-named establishments.
