What are the differences within/between Pokemon series?

Question

My kids are getting interested in Pokemon TCG, so I'm trying to figure out the different series and sets. I played Magic the Gathering for a little while, which has helped me understand some of the terminology (e.g., starter sets, theme decks, booster packs), but some things seem to be different. Specifically: what are the differences within/between Pokemon series?

For example, what are the differences between the Black & White Dragons Exalted set and the Black & White Emerging Powers set? And what are the differences between the Black & White series and the Heartgold & Soulsilver series?

I understand that the different sets/series have different cards in them, but is there anything else? In Magic the Gathering, the different expansion sets had extra mechanics not seen in the core set. Note that I'm more interested in the differences pertaining to gameplay than to collecting.

Answer 1

It's not the set theirselves, it's the "era". BW: Dragons Exalted and BW: Emerging Powers are from the same era and share the same mechanics (although starting from BW: Next Destinies Pokémon EX were introduced, and from BW: Plasma Storm we got Team Plasma cards with certain advantages when combined with other cards that give them effects).

However, the Black & White series and the HeartGold & SoulSilver series are different in that, given the former has Pokémon EX and Team Plasma Pokémon, the latter has Pokémon Prime and Pokémon LEGEND (Prime cards are more powerful versions of certain Pokémon, and LEGEND cards are Pokémon that can only be played by having both parts of the whole card in your hand).

Sometimes the rules change over the eras aswell. In BW some cards received errata (such as Rare Candy) and certain rules were reworked (such as who goes first), but besides that the game remains largely the same.

Hope that helps.

Answer 2

Official tournaments use a set rotation system. This means that only the newest sets are legal for tournament play. Since Pokémon offers tournaments on a very casual level, this is definitely a point to consider.
What sets are currently legal changes once a year, usually around September. Any new set that is released automatically becomes legal (for higher level tournaments such as National Chamionships, there is a small delay between the street date and the date when it becomes legal for tournament play).

Most of the time, the number of legal sets after a rotation occured in September is roughly 5-8. Right before the rotation (at the time the World Championships take place), it's usually 9-12.

The time between 2 rotations is called a Season. All achievements, point scores and similar things connected to tournaments and leagues ("Organized Play"), notably the age group players are assigned, are reset at the start of each Season.

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Game Mechanics (rules), while slightly changing with each era (see the other answer), usually stay mainly the same.

Strategic Mechanics, however, generally change a lot between eras. Sometimes, Basic Pokémon play the most important role, sometimes Evolved Pokémon do (right now, as of X&Y, Evolved Pokémon are back on the rise). Searching Pokémon out of the deck is sometimes based mainly on other Pokémon's abilities, other times on Supporters or Items. Some eras have very strong Energy manipulation, others are very disruptive, still others rely on damage manipulation a lot.
Some eras even use completely new mechanics which are not present in older (or newer) sets. An example for this is the Heartgold & Soulsilver era, which introduced the Lost Zone, an area nowhere on the field where cards could never return from (within one game), as well as several cards referring to this area and using it (for example, Lost World allowed a player to declare himself the winner if at least 6 of the opponent's Pokémon were in the Lost Zone, while Mew was able to use any attacks of Pokémon in the Lost Zone). This concept was never used again after Call of Legends.